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-rw-r--r--Cargo.lock14
-rw-r--r--compiler/rustc_ast/src/ast.rs18
-rw-r--r--compiler/rustc_ast/src/mut_visit.rs3
-rw-r--r--compiler/rustc_ast/src/token.rs6
-rw-r--r--compiler/rustc_ast/src/tokenstream.rs13
-rw-r--r--compiler/rustc_ast/src/visit.rs7
-rw-r--r--compiler/rustc_ast_lowering/src/expr.rs9
-rw-r--r--compiler/rustc_ast_lowering/src/lib.rs63
-rw-r--r--compiler/rustc_ast_lowering/src/pat.rs3
-rw-r--r--compiler/rustc_ast_passes/src/feature_gate.rs3
-rw-r--r--compiler/rustc_ast_pretty/src/pprust/state.rs6
-rw-r--r--compiler/rustc_ast_pretty/src/pprust/state/expr.rs20
-rw-r--r--compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs2
-rw-r--r--compiler/rustc_borrowck/src/region_infer/opaque_types.rs9
-rw-r--r--compiler/rustc_builtin_macros/src/assert/context.rs2
-rw-r--r--compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs2
-rw-r--r--compiler/rustc_builtin_macros/src/deriving/debug.rs3
-rw-r--r--compiler/rustc_builtin_macros/src/lib.rs2
-rw-r--r--compiler/rustc_builtin_macros/src/type_ascribe.rs35
-rw-r--r--compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs10
-rw-r--r--compiler/rustc_codegen_ssa/src/back/command.rs6
-rw-r--r--compiler/rustc_codegen_ssa/src/back/link.rs17
-rw-r--r--compiler/rustc_codegen_ssa/src/traits/backend.rs7
-rw-r--r--compiler/rustc_const_eval/src/interpret/memory.rs17
-rw-r--r--compiler/rustc_const_eval/src/transform/validate.rs13
-rw-r--r--compiler/rustc_data_structures/src/sync.rs9
-rw-r--r--compiler/rustc_driver_impl/src/lib.rs4
-rw-r--r--compiler/rustc_expand/messages.ftl3
-rw-r--r--compiler/rustc_expand/src/build.rs4
-rw-r--r--compiler/rustc_expand/src/errors.rs8
-rw-r--r--compiler/rustc_expand/src/mbe/macro_parser.rs17
-rw-r--r--compiler/rustc_expand/src/mbe/macro_rules.rs8
-rw-r--r--compiler/rustc_expand/src/mbe/quoted.rs8
-rw-r--r--compiler/rustc_expand/src/mbe/transcribe.rs31
-rw-r--r--compiler/rustc_feature/src/builtin_attrs.rs7
-rw-r--r--compiler/rustc_feature/src/unstable.rs4
-rw-r--r--compiler/rustc_hir/src/def.rs2
-rw-r--r--compiler/rustc_hir/src/hir.rs30
-rw-r--r--compiler/rustc_hir/src/intravisit.rs6
-rw-r--r--compiler/rustc_hir/src/lang_items.rs1
-rw-r--r--compiler/rustc_hir_analysis/src/astconv/bounds.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/check/compare_impl_item.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/check/mod.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/check/region.rs2
-rw-r--r--compiler/rustc_hir_analysis/src/collect.rs13
-rw-r--r--compiler/rustc_hir_analysis/src/collect/item_bounds.rs54
-rw-r--r--compiler/rustc_hir_analysis/src/collect/type_of.rs6
-rw-r--r--compiler/rustc_hir_analysis/src/hir_wf_check.rs10
-rw-r--r--compiler/rustc_hir_pretty/src/lib.rs8
-rw-r--r--compiler/rustc_hir_typeck/src/_match.rs4
-rw-r--r--compiler/rustc_hir_typeck/src/closure.rs4
-rw-r--r--compiler/rustc_hir_typeck/src/expr.rs6
-rw-r--r--compiler/rustc_hir_typeck/src/expr_use_visitor.rs3
-rw-r--r--compiler/rustc_hir_typeck/src/fallback.rs36
-rw-r--r--compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs27
-rw-r--r--compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs73
-rw-r--r--compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs2
-rw-r--r--compiler/rustc_hir_typeck/src/gather_locals.rs8
-rw-r--r--compiler/rustc_hir_typeck/src/mem_categorization.rs2
-rw-r--r--compiler/rustc_hir_typeck/src/op.rs4
-rw-r--r--compiler/rustc_hir_typeck/src/pat.rs28
-rw-r--r--compiler/rustc_incremental/src/persist/dirty_clean.rs2
-rw-r--r--compiler/rustc_index_macros/src/lib.rs8
-rw-r--r--compiler/rustc_index_macros/src/newtype.rs28
-rw-r--r--compiler/rustc_infer/src/infer/error_reporting/mod.rs9
-rw-r--r--compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs77
-rw-r--r--compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs71
-rw-r--r--compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs12
-rw-r--r--compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs19
-rw-r--r--compiler/rustc_infer/src/infer/opaque_types/mod.rs3
-rw-r--r--compiler/rustc_infer/src/infer/outlives/verify.rs2
-rw-r--r--compiler/rustc_infer/src/infer/region_constraints/mod.rs2
-rw-r--r--compiler/rustc_infer/src/lib.rs1
-rw-r--r--compiler/rustc_interface/src/interface.rs55
-rw-r--r--compiler/rustc_interface/src/tests.rs5
-rw-r--r--compiler/rustc_lint/src/unused.rs10
-rw-r--r--compiler/rustc_metadata/src/rmeta/decoder.rs14
-rw-r--r--compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs1
-rw-r--r--compiler/rustc_metadata/src/rmeta/encoder.rs8
-rw-r--r--compiler/rustc_metadata/src/rmeta/mod.rs1
-rw-r--r--compiler/rustc_middle/src/hir/map/mod.rs12
-rw-r--r--compiler/rustc_middle/src/hir/mod.rs18
-rw-r--r--compiler/rustc_middle/src/macros.rs28
-rw-r--r--compiler/rustc_middle/src/mir/coverage.rs5
-rw-r--r--compiler/rustc_middle/src/mir/interpret/allocation.rs42
-rw-r--r--compiler/rustc_middle/src/mir/mod.rs46
-rw-r--r--compiler/rustc_middle/src/mir/syntax.rs1
-rw-r--r--compiler/rustc_middle/src/query/mod.rs32
-rw-r--r--compiler/rustc_middle/src/thir.rs9
-rw-r--r--compiler/rustc_middle/src/thir/visit.rs1
-rw-r--r--compiler/rustc_middle/src/ty/context.rs2
-rw-r--r--compiler/rustc_middle/src/ty/diagnostics.rs28
-rw-r--r--compiler/rustc_middle/src/ty/region.rs1
-rw-r--r--compiler/rustc_middle/src/ty/util.rs36
-rw-r--r--compiler/rustc_mir_build/src/build/custom/mod.rs1
-rw-r--r--compiler/rustc_mir_build/src/build/matches/mod.rs4
-rw-r--r--compiler/rustc_mir_build/src/build/matches/util.rs6
-rw-r--r--compiler/rustc_mir_build/src/check_unsafety.rs3
-rw-r--r--compiler/rustc_mir_build/src/thir/pattern/check_match.rs1
-rw-r--r--compiler/rustc_mir_build/src/thir/pattern/mod.rs3
-rw-r--r--compiler/rustc_mir_build/src/thir/print.rs6
-rw-r--r--compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs13
-rw-r--r--compiler/rustc_mir_transform/src/coverage/counters.rs39
-rw-r--r--compiler/rustc_mir_transform/src/inline.rs21
-rw-r--r--compiler/rustc_mir_transform/src/lib.rs5
-rw-r--r--compiler/rustc_mir_transform/src/mentioned_items.rs117
-rw-r--r--compiler/rustc_mir_transform/src/shim.rs4
-rw-r--r--compiler/rustc_monomorphize/src/collector.rs843
-rw-r--r--compiler/rustc_monomorphize/src/partitioning.rs14
-rw-r--r--compiler/rustc_parse/messages.ftl2
-rw-r--r--compiler/rustc_parse/src/errors.rs7
-rw-r--r--compiler/rustc_parse/src/parser/attr.rs47
-rw-r--r--compiler/rustc_parse/src/parser/expr.rs59
-rw-r--r--compiler/rustc_parse/src/parser/item.rs14
-rw-r--r--compiler/rustc_parse/src/parser/mod.rs49
-rw-r--r--compiler/rustc_parse/src/parser/nonterminal.rs15
-rw-r--r--compiler/rustc_parse/src/parser/pat.rs22
-rw-r--r--compiler/rustc_parse/src/parser/stmt.rs20
-rw-r--r--compiler/rustc_parse/src/parser/ty.rs2
-rw-r--r--compiler/rustc_passes/src/check_const.rs2
-rw-r--r--compiler/rustc_passes/src/dead.rs4
-rw-r--r--compiler/rustc_passes/src/hir_stats.rs2
-rw-r--r--compiler/rustc_passes/src/reachable.rs2
-rw-r--r--compiler/rustc_pattern_analysis/Cargo.toml4
-rw-r--r--compiler/rustc_pattern_analysis/src/constructor.rs75
-rw-r--r--compiler/rustc_pattern_analysis/src/lib.rs9
-rw-r--r--compiler/rustc_pattern_analysis/src/pat.rs80
-rw-r--r--compiler/rustc_pattern_analysis/src/rustc.rs13
-rw-r--r--compiler/rustc_pattern_analysis/src/usefulness.rs25
-rw-r--r--compiler/rustc_pattern_analysis/tests/common/mod.rs315
-rw-r--r--compiler/rustc_pattern_analysis/tests/complexity.rs109
-rw-r--r--compiler/rustc_pattern_analysis/tests/exhaustiveness.rs77
-rw-r--r--compiler/rustc_pattern_analysis/tests/intersection.rs69
-rw-r--r--compiler/rustc_privacy/src/lib.rs2
-rw-r--r--compiler/rustc_resolve/src/late.rs48
-rw-r--r--compiler/rustc_resolve/src/late/diagnostics.rs21
-rw-r--r--compiler/rustc_session/src/config.rs45
-rw-r--r--compiler/rustc_session/src/session.rs9
-rw-r--r--compiler/rustc_smir/src/rustc_internal/internal.rs46
-rw-r--r--compiler/rustc_smir/src/rustc_internal/pretty.rs2
-rw-r--r--compiler/rustc_smir/src/rustc_smir/context.rs15
-rw-r--r--compiler/rustc_span/src/symbol.rs13
-rw-r--r--compiler/rustc_symbol_mangling/src/test.rs2
-rw-r--r--compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs22
-rw-r--r--compiler/rustc_target/src/spec/mod.rs4
-rw-r--r--compiler/rustc_target/src/spec/targets/riscv32ima_unknown_none_elf.rs29
-rw-r--r--compiler/rustc_trait_selection/messages.ftl9
-rw-r--r--compiler/rustc_trait_selection/src/solve/assembly/mod.rs9
-rw-r--r--compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs36
-rw-r--r--compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs7
-rw-r--r--compiler/rustc_trait_selection/src/solve/trait_goals.rs22
-rw-r--r--compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs189
-rw-r--r--compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs10
-rw-r--r--compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs33
-rw-r--r--compiler/rustc_trait_selection/src/traits/select/confirmation.rs10
-rw-r--r--compiler/rustc_trait_selection/src/traits/select/mod.rs38
-rw-r--r--compiler/rustc_type_ir/src/flags.rs2
-rw-r--r--compiler/stable_mir/src/compiler_interface.rs10
-rw-r--r--compiler/stable_mir/src/lib.rs6
-rw-r--r--compiler/stable_mir/src/mir/body.rs30
-rw-r--r--compiler/stable_mir/src/mir/mono.rs6
-rw-r--r--compiler/stable_mir/src/mir/pretty.rs521
-rw-r--r--config.example.toml2
-rw-r--r--library/alloc/src/collections/btree/map.rs5
-rw-r--r--library/alloc/src/collections/btree/set.rs6
-rw-r--r--library/alloc/src/sync.rs2
-rw-r--r--library/alloc/src/vec/in_place_collect.rs168
-rw-r--r--library/alloc/src/vec/mod.rs7
-rw-r--r--library/alloc/tests/vec.rs41
-rw-r--r--library/core/src/alloc/global.rs9
-rw-r--r--library/core/src/iter/traits/marker.rs1
-rw-r--r--library/core/src/macros/mod.rs16
-rw-r--r--library/core/src/option.rs92
-rw-r--r--library/core/src/prelude/v1.rs8
-rw-r--r--library/panic_unwind/src/emcc.rs2
-rw-r--r--library/proc_macro/src/bridge/handle.rs4
-rw-r--r--library/std/src/alloc.rs6
-rw-r--r--library/std/src/net/test.rs4
-rw-r--r--library/std/src/os/freebsd/net.rs26
-rw-r--r--library/std/src/os/netbsd/net.rs26
-rw-r--r--library/std/src/panicking.rs2
-rw-r--r--library/std/src/prelude/v1.rs9
-rw-r--r--library/std/src/sync/condvar/tests.rs4
-rw-r--r--library/std/src/sys/pal/unix/net.rs31
-rw-r--r--library/std/src/sys/pal/unix/thread_parking/pthread.rs22
-rw-r--r--library/std/src/sys/pal/wasm/alloc.rs9
-rw-r--r--library/std/src/sys/pal/windows/pipe.rs8
-rw-r--r--library/std/src/sys/pal/xous/alloc.rs9
-rw-r--r--library/std/src/sys/pal/xous/net/tcpstream.rs2
-rw-r--r--library/std/src/sys/pal/xous/thread_local_key.rs10
-rw-r--r--library/std/src/sys/sync/mutex/xous.rs11
-rw-r--r--library/std/src/sys_common/thread_local_key.rs6
-rw-r--r--library/std/src/thread/local/tests.rs19
-rw-r--r--src/bootstrap/src/lib.rs29
-rw-r--r--src/ci/docker/host-x86_64/test-various/Dockerfile4
-rw-r--r--src/doc/rustc/src/platform-support.md1
-rw-r--r--src/doc/rustc/src/platform-support/riscv32-unknown-none-elf.md6
-rw-r--r--src/doc/unstable-book/src/language-features/postfix-match.md22
-rw-r--r--src/librustdoc/clean/mod.rs5
-rw-r--r--src/librustdoc/clean/utils.rs1
m---------src/llvm-project0
-rw-r--r--src/tools/build-manifest/src/main.rs1
-rw-r--r--src/tools/clippy/.github/workflows/clippy.yml10
-rw-r--r--src/tools/clippy/.github/workflows/clippy_bors.yml25
-rw-r--r--src/tools/clippy/CHANGELOG.md63
-rw-r--r--src/tools/clippy/Cargo.toml12
-rw-r--r--src/tools/clippy/book/src/development/macro_expansions.md4
-rw-r--r--src/tools/clippy/book/src/lint_configuration.md1
-rw-r--r--src/tools/clippy/clippy.toml13
-rw-r--r--src/tools/clippy/clippy_config/Cargo.toml2
-rw-r--r--src/tools/clippy/clippy_config/src/conf.rs2
-rw-r--r--src/tools/clippy/clippy_config/src/msrvs.rs1
-rw-r--r--src/tools/clippy/clippy_dev/src/update_lints.rs2
-rw-r--r--src/tools/clippy/clippy_lints/Cargo.toml2
-rw-r--r--src/tools/clippy/clippy_lints/src/assigning_clones.rs29
-rw-r--r--src/tools/clippy/clippy_lints/src/attrs/duplicated_attributes.rs64
-rw-r--r--src/tools/clippy/clippy_lints/src/attrs/mod.rs35
-rw-r--r--src/tools/clippy/clippy_lints/src/box_default.rs4
-rw-r--r--src/tools/clippy/clippy_lints/src/casts/cast_lossless.rs41
-rw-r--r--src/tools/clippy/clippy_lints/src/casts/mod.rs2
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-rw-r--r--src/tools/clippy/clippy_lints/src/doc/markdown.rs17
-rw-r--r--src/tools/clippy/clippy_lints/src/doc/mod.rs24
-rw-r--r--src/tools/clippy/clippy_lints/src/else_if_without_else.rs26
-rw-r--r--src/tools/clippy/clippy_lints/src/entry.rs5
-rw-r--r--src/tools/clippy/clippy_lints/src/equatable_if_let.rs2
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-rw-r--r--src/tools/clippy/clippy_lints/src/integer_division_remainder_used.rs50
-rw-r--r--src/tools/clippy/clippy_lints/src/let_if_seq.rs5
-rw-r--r--src/tools/clippy/clippy_lints/src/lib.rs8
-rw-r--r--src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs2
-rw-r--r--src/tools/clippy/clippy_lints/src/loops/never_loop.rs4
-rw-r--r--src/tools/clippy/clippy_lints/src/loops/unused_enumerate_index.rs81
-rw-r--r--src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs2
-rw-r--r--src/tools/clippy/clippy_lints/src/manual_retain.rs11
-rw-r--r--src/tools/clippy/clippy_lints/src/manual_unwrap_or_default.rs181
-rw-r--r--src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs2
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-rw-r--r--src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs2
-rw-r--r--src/tools/clippy/clippy_lints/src/methods/is_empty.rs49
-rw-r--r--src/tools/clippy/clippy_lints/src/methods/iter_nth.rs49
-rw-r--r--src/tools/clippy/clippy_lints/src/methods/map_clone.rs11
-rw-r--r--src/tools/clippy/clippy_lints/src/methods/mod.rs143
-rw-r--r--src/tools/clippy/clippy_lints/src/methods/no_effect_replace.rs1
-rw-r--r--src/tools/clippy/clippy_lints/src/methods/unused_enumerate_index.rs135
-rw-r--r--src/tools/clippy/clippy_lints/src/missing_doc.rs64
-rw-r--r--src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs17
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-rw-r--r--src/tools/clippy/declare_clippy_lint/Cargo.toml2
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-rw-r--r--tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.rs1
-rw-r--r--tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.stderr18
-rw-r--r--tests/ui/parser/attribute/attr-bad-meta-4.rs12
-rw-r--r--tests/ui/parser/attribute/attr-bad-meta-4.stderr25
-rw-r--r--tests/ui/pattern/deref-patterns/typeck.rs31
-rw-r--r--tests/ui/raw-ref-op/raw-ref-temp.stderr8
-rw-r--r--tests/ui/reachable/expr_type.stderr1
-rw-r--r--tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-parse-not-item.stderr10
-rw-r--r--tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.rs6
-rw-r--r--tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.stderr14
-rw-r--r--tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs18
-rw-r--r--tests/ui/stable-mir-print/basic_function.rs13
-rw-r--r--tests/ui/stable-mir-print/basic_function.stdout266
-rw-r--r--tests/ui/suggestions/issue-85347.rs3
-rw-r--r--tests/ui/suggestions/issue-85347.stderr27
-rw-r--r--tests/ui/suggestions/issue-86667.rs2
-rw-r--r--tests/ui/suggestions/issue-86667.stderr22
-rw-r--r--tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs12
-rw-r--r--tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr20
-rw-r--r--tests/ui/suggestions/missing-lifetime-specifier.rs10
-rw-r--r--tests/ui/suggestions/missing-lifetime-specifier.stderr228
-rw-r--r--tests/ui/suggestions/types/into-inference-needs-type.rs15
-rw-r--r--tests/ui/suggestions/types/into-inference-needs-type.stderr19
-rw-r--r--tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.rs1
-rw-r--r--tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.stderr29
-rw-r--r--tests/ui/traits/impl-of-supertrait-has-wrong-lifetime-parameters.stderr12
-rw-r--r--tests/ui/traits/matching-lifetimes.stderr24
-rw-r--r--tests/ui/traits/span-bug-issue-121414.rs3
-rw-r--r--tests/ui/traits/span-bug-issue-121414.stderr21
-rw-r--r--tests/ui/traits/suggest-fully-qualified-closure.rs2
-rw-r--r--tests/ui/traits/suggest-fully-qualified-closure.stderr8
-rw-r--r--tests/ui/type-alias-impl-trait/hkl_forbidden4.rs25
-rw-r--r--tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr34
-rw-r--r--tests/ui/type-alias-impl-trait/not_well_formed.fixed19
-rw-r--r--tests/ui/type-alias-impl-trait/not_well_formed.rs6
-rw-r--r--tests/ui/type-alias-impl-trait/not_well_formed.stderr14
-rw-r--r--tests/ui/typeck/escaping_bound_vars.rs3
-rw-r--r--tests/ui/typeck/escaping_bound_vars.stderr47
-rw-r--r--tests/ui/typeck/issue-91267.stderr2
-rw-r--r--tests/ui/unboxed-closures/unboxed-closure-sugar-region.rs1
-rw-r--r--tests/ui/unboxed-closures/unboxed-closure-sugar-region.stderr20
-rw-r--r--tests/ui/unboxed-closures/unboxed-closures-type-mismatch-closure-from-another-scope.stderr6
-rw-r--r--tests/ui/underscore-lifetime/underscore-lifetime-binders.rs1
-rw-r--r--tests/ui/underscore-lifetime/underscore-lifetime-binders.stderr10
-rw-r--r--tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs12
-rw-r--r--tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr60
-rw-r--r--tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.rs1
-rw-r--r--tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.stderr17
620 files changed, 10745 insertions, 4002 deletions
diff --git a/Cargo.lock b/Cargo.lock
index 3110f32ade9..e97d29d57ee 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -574,7 +574,7 @@ checksum = "98cc8fbded0c607b7ba9dd60cd98df59af97e84d24e49c8557331cfc26d301ce"
 
 [[package]]
 name = "clippy"
-version = "0.1.78"
+version = "0.1.79"
 dependencies = [
  "anstream",
  "clippy_config",
@@ -602,7 +602,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_config"
-version = "0.1.78"
+version = "0.1.79"
 dependencies = [
  "rustc-semver",
  "serde",
@@ -625,7 +625,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_lints"
-version = "0.1.78"
+version = "0.1.79"
 dependencies = [
  "arrayvec",
  "cargo_metadata 0.18.1",
@@ -650,7 +650,7 @@ dependencies = [
 
 [[package]]
 name = "clippy_utils"
-version = "0.1.78"
+version = "0.1.79"
 dependencies = [
  "arrayvec",
  "clippy_config",
@@ -971,7 +971,7 @@ checksum = "a0afaad2b26fa326569eb264b1363e8ae3357618c43982b3f285f0774ce76b69"
 
 [[package]]
 name = "declare_clippy_lint"
-version = "0.1.78"
+version = "0.1.79"
 dependencies = [
  "itertools 0.12.1",
  "quote",
@@ -2205,7 +2205,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c2a198fb6b0eada2a8df47933734e6d35d350665a33a3593d7164fa52c75c19"
 dependencies = [
  "cfg-if",
- "windows-targets 0.52.4",
+ "windows-targets 0.48.5",
 ]
 
 [[package]]
@@ -4440,6 +4440,8 @@ dependencies = [
  "rustc_target",
  "smallvec",
  "tracing",
+ "tracing-subscriber",
+ "tracing-tree",
 ]
 
 [[package]]
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index d0e8b86b71d..f14b0d3200c 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -621,7 +621,9 @@ impl Pat {
             | PatKind::Or(s) => s.iter().for_each(|p| p.walk(it)),
 
             // Trivial wrappers over inner patterns.
-            PatKind::Box(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => s.walk(it),
+            PatKind::Box(s) | PatKind::Deref(s) | PatKind::Ref(s, _) | PatKind::Paren(s) => {
+                s.walk(it)
+            }
 
             // These patterns do not contain subpatterns, skip.
             PatKind::Wild
@@ -792,6 +794,9 @@ pub enum PatKind {
     /// A `box` pattern.
     Box(P<Pat>),
 
+    /// A `deref` pattern (currently `deref!()` macro-based syntax).
+    Deref(P<Pat>),
+
     /// A reference pattern (e.g., `&mut (a, b)`).
     Ref(P<Pat>, Mutability),
 
@@ -1436,7 +1441,7 @@ pub enum ExprKind {
     /// `'label: loop { block }`
     Loop(P<Block>, Option<Label>, Span),
     /// A `match` block.
-    Match(P<Expr>, ThinVec<Arm>),
+    Match(P<Expr>, ThinVec<Arm>, MatchKind),
     /// A closure (e.g., `move |a, b, c| a + b + c`).
     Closure(Box<Closure>),
     /// A block (`'label: { ... }`).
@@ -1761,6 +1766,15 @@ pub enum StrStyle {
     Raw(u8),
 }
 
+/// The kind of match expression
+#[derive(Clone, Copy, Encodable, Decodable, Debug, PartialEq)]
+pub enum MatchKind {
+    /// match expr { ... }
+    Prefix,
+    /// expr.match { ... }
+    Postfix,
+}
+
 /// A literal in a meta item.
 #[derive(Clone, Encodable, Decodable, Debug, HashStable_Generic)]
 pub struct MetaItemLit {
diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index 83468c5f101..7337b969242 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -1295,6 +1295,7 @@ pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
             fields.flat_map_in_place(|field| vis.flat_map_pat_field(field));
         }
         PatKind::Box(inner) => vis.visit_pat(inner),
+        PatKind::Deref(inner) => vis.visit_pat(inner),
         PatKind::Ref(inner, _mutbl) => vis.visit_pat(inner),
         PatKind::Range(e1, e2, Spanned { span: _, node: _ }) => {
             visit_opt(e1, |e| vis.visit_expr(e));
@@ -1424,7 +1425,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
             visit_opt(label, |label| vis.visit_label(label));
             vis.visit_span(span);
         }
-        ExprKind::Match(expr, arms) => {
+        ExprKind::Match(expr, arms, _kind) => {
             vis.visit_expr(expr);
             arms.flat_map_in_place(|arm| vis.flat_map_arm(arm));
         }
diff --git a/compiler/rustc_ast/src/token.rs b/compiler/rustc_ast/src/token.rs
index c17020ed663..f49eb2f22c5 100644
--- a/compiler/rustc_ast/src/token.rs
+++ b/compiler/rustc_ast/src/token.rs
@@ -105,7 +105,7 @@ impl Lit {
         }
     }
 
-    /// Keep this in sync with `Token::can_begin_literal_or_bool` excluding unary negation.
+    /// Keep this in sync with `Token::can_begin_literal_maybe_minus` excluding unary negation.
     pub fn from_token(token: &Token) -> Option<Lit> {
         match token.uninterpolate().kind {
             Ident(name, IdentIsRaw::No) if name.is_bool_lit() => Some(Lit::new(Bool, name, None)),
@@ -664,7 +664,7 @@ impl Token {
     }
 
     /// Returns `true` if the token is an interpolated path.
-    fn is_path(&self) -> bool {
+    fn is_whole_path(&self) -> bool {
         if let Interpolated(nt) = &self.kind
             && let NtPath(..) = &nt.0
         {
@@ -710,7 +710,7 @@ impl Token {
     pub fn is_path_start(&self) -> bool {
         self == &ModSep
             || self.is_qpath_start()
-            || self.is_path()
+            || self.is_whole_path()
             || self.is_path_segment_keyword()
             || self.is_ident() && !self.is_reserved_ident()
     }
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index adc3056cc29..239735456ad 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -28,18 +28,7 @@ use smallvec::{smallvec, SmallVec};
 use std::borrow::Cow;
 use std::{cmp, fmt, iter};
 
-/// When the main Rust parser encounters a syntax-extension invocation, it
-/// parses the arguments to the invocation as a token tree. This is a very
-/// loose structure, such that all sorts of different AST fragments can
-/// be passed to syntax extensions using a uniform type.
-///
-/// If the syntax extension is an MBE macro, it will attempt to match its
-/// LHS token tree against the provided token tree, and if it finds a
-/// match, will transcribe the RHS token tree, splicing in any captured
-/// `macro_parser::matched_nonterminals` into the `SubstNt`s it finds.
-///
-/// The RHS of an MBE macro is the only place `SubstNt`s are substituted.
-/// Nothing special happens to misnamed or misplaced `SubstNt`s.
+/// Part of a `TokenStream`.
 #[derive(Debug, Clone, PartialEq, Encodable, Decodable, HashStable_Generic)]
 pub enum TokenTree {
     /// A single token. Should never be `OpenDelim` or `CloseDelim`, because
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 825f8dad8e4..085ca2b82e7 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -576,7 +576,10 @@ pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) -> V::Res
             try_visit!(visitor.visit_path(path, pattern.id));
             walk_list!(visitor, visit_pat_field, fields);
         }
-        PatKind::Box(subpattern) | PatKind::Ref(subpattern, _) | PatKind::Paren(subpattern) => {
+        PatKind::Box(subpattern)
+        | PatKind::Deref(subpattern)
+        | PatKind::Ref(subpattern, _)
+        | PatKind::Paren(subpattern) => {
             try_visit!(visitor.visit_pat(subpattern));
         }
         PatKind::Ident(_, ident, optional_subpattern) => {
@@ -920,7 +923,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) -> V
             visit_opt!(visitor, visit_label, opt_label);
             try_visit!(visitor.visit_block(block));
         }
-        ExprKind::Match(subexpression, arms) => {
+        ExprKind::Match(subexpression, arms, _kind) => {
             try_visit!(visitor.visit_expr(subexpression));
             walk_list!(visitor, visit_arm, arms);
         }
diff --git a/compiler/rustc_ast_lowering/src/expr.rs b/compiler/rustc_ast_lowering/src/expr.rs
index 41f7418ddde..389cf4e3132 100644
--- a/compiler/rustc_ast_lowering/src/expr.rs
+++ b/compiler/rustc_ast_lowering/src/expr.rs
@@ -157,7 +157,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     hir::ExprKind::AddrOf(*k, *m, ohs)
                 }
                 ExprKind::Let(pat, scrutinee, span, is_recovered) => {
-                    hir::ExprKind::Let(self.arena.alloc(hir::Let {
+                    hir::ExprKind::Let(self.arena.alloc(hir::LetExpr {
                         span: self.lower_span(*span),
                         pat: self.lower_pat(pat),
                         ty: None,
@@ -181,10 +181,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     )
                 }),
                 ExprKind::TryBlock(body) => self.lower_expr_try_block(body),
-                ExprKind::Match(expr, arms) => hir::ExprKind::Match(
+                ExprKind::Match(expr, arms, kind) => hir::ExprKind::Match(
                     self.lower_expr(expr),
                     self.arena.alloc_from_iter(arms.iter().map(|x| self.lower_arm(x))),
-                    hir::MatchSource::Normal,
+                    match kind {
+                        MatchKind::Prefix => hir::MatchSource::Normal,
+                        MatchKind::Postfix => hir::MatchSource::Postfix,
+                    },
                 ),
                 ExprKind::Await(expr, await_kw_span) => self.lower_expr_await(*await_kw_span, expr),
                 ExprKind::Closure(box Closure {
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 6a7ee936f66..d2744e8ff68 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -55,7 +55,9 @@ use rustc_errors::{DiagArgFromDisplay, DiagCtxt, StashKey};
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, LifetimeRes, Namespace, PartialRes, PerNS, Res};
 use rustc_hir::def_id::{LocalDefId, LocalDefIdMap, CRATE_DEF_ID, LOCAL_CRATE};
-use rustc_hir::{ConstArg, GenericArg, ItemLocalMap, ParamName, TraitCandidate};
+use rustc_hir::{
+    ConstArg, GenericArg, ItemLocalMap, MissingLifetimeKind, ParamName, TraitCandidate,
+};
 use rustc_index::{Idx, IndexSlice, IndexVec};
 use rustc_macros::extension;
 use rustc_middle::span_bug;
@@ -797,7 +799,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             LifetimeRes::Param { .. } => {
                 (hir::ParamName::Plain(ident), hir::LifetimeParamKind::Explicit)
             }
-            LifetimeRes::Fresh { param, .. } => {
+            LifetimeRes::Fresh { param, kind, .. } => {
                 // Late resolution delegates to us the creation of the `LocalDefId`.
                 let _def_id = self.create_def(
                     self.current_hir_id_owner.def_id,
@@ -808,7 +810,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 );
                 debug!(?_def_id);
 
-                (hir::ParamName::Fresh, hir::LifetimeParamKind::Elided)
+                (hir::ParamName::Fresh, hir::LifetimeParamKind::Elided(kind))
             }
             LifetimeRes::Static | LifetimeRes::Error => return None,
             res => panic!(
@@ -1605,13 +1607,13 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
         for lifetime in captured_lifetimes_to_duplicate {
             let res = self.resolver.get_lifetime_res(lifetime.id).unwrap_or(LifetimeRes::Error);
-            let old_def_id = match res {
-                LifetimeRes::Param { param: old_def_id, binder: _ } => old_def_id,
+            let (old_def_id, missing_kind) = match res {
+                LifetimeRes::Param { param: old_def_id, binder: _ } => (old_def_id, None),
 
-                LifetimeRes::Fresh { param, binder: _ } => {
+                LifetimeRes::Fresh { param, kind, .. } => {
                     debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
                     if let Some(old_def_id) = self.orig_opt_local_def_id(param) {
-                        old_def_id
+                        (old_def_id, Some(kind))
                     } else {
                         self.dcx()
                             .span_delayed_bug(lifetime.ident.span, "no def-id for fresh lifetime");
@@ -1651,6 +1653,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     duplicated_lifetime_node_id,
                     duplicated_lifetime_def_id,
                     self.lower_ident(lifetime.ident),
+                    missing_kind,
                 ));
 
                 // Now make an arg that we can use for the generic params of the opaque tykind.
@@ -1668,27 +1671,33 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
             let bounds = this
                 .with_remapping(captured_to_synthesized_mapping, |this| lower_item_bounds(this));
 
-            let generic_params = this.arena.alloc_from_iter(
-                synthesized_lifetime_definitions.iter().map(|&(new_node_id, new_def_id, ident)| {
-                    let hir_id = this.lower_node_id(new_node_id);
-                    let (name, kind) = if ident.name == kw::UnderscoreLifetime {
-                        (hir::ParamName::Fresh, hir::LifetimeParamKind::Elided)
-                    } else {
-                        (hir::ParamName::Plain(ident), hir::LifetimeParamKind::Explicit)
-                    };
+            let generic_params =
+                this.arena.alloc_from_iter(synthesized_lifetime_definitions.iter().map(
+                    |&(new_node_id, new_def_id, ident, missing_kind)| {
+                        let hir_id = this.lower_node_id(new_node_id);
+                        let (name, kind) = if ident.name == kw::UnderscoreLifetime {
+                            (
+                                hir::ParamName::Fresh,
+                                hir::LifetimeParamKind::Elided(
+                                    missing_kind.unwrap_or(MissingLifetimeKind::Underscore),
+                                ),
+                            )
+                        } else {
+                            (hir::ParamName::Plain(ident), hir::LifetimeParamKind::Explicit)
+                        };
 
-                    hir::GenericParam {
-                        hir_id,
-                        def_id: new_def_id,
-                        name,
-                        span: ident.span,
-                        pure_wrt_drop: false,
-                        kind: hir::GenericParamKind::Lifetime { kind },
-                        colon_span: None,
-                        source: hir::GenericParamSource::Generics,
-                    }
-                }),
-            );
+                        hir::GenericParam {
+                            hir_id,
+                            def_id: new_def_id,
+                            name,
+                            span: ident.span,
+                            pure_wrt_drop: false,
+                            kind: hir::GenericParamKind::Lifetime { kind },
+                            colon_span: None,
+                            source: hir::GenericParamSource::Generics,
+                        }
+                    },
+                ));
             debug!("lower_async_fn_ret_ty: generic_params={:#?}", generic_params);
 
             let lifetime_mapping = self.arena.alloc_slice(&synthesized_lifetime_args);
diff --git a/compiler/rustc_ast_lowering/src/pat.rs b/compiler/rustc_ast_lowering/src/pat.rs
index 469cdac11e4..8631d90be81 100644
--- a/compiler/rustc_ast_lowering/src/pat.rs
+++ b/compiler/rustc_ast_lowering/src/pat.rs
@@ -91,6 +91,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     PatKind::Box(inner) => {
                         break hir::PatKind::Box(self.lower_pat(inner));
                     }
+                    PatKind::Deref(inner) => {
+                        break hir::PatKind::Deref(self.lower_pat(inner));
+                    }
                     PatKind::Ref(inner, mutbl) => {
                         break hir::PatKind::Ref(self.lower_pat(inner), *mutbl);
                     }
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index 2c396a64789..bb83f4c0f0e 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -564,6 +564,7 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
     gate_all!(generic_const_items, "generic const items are experimental");
     gate_all!(unnamed_fields, "unnamed fields are not yet fully implemented");
     gate_all!(fn_delegation, "functions delegation is not yet fully implemented");
+    gate_all!(postfix_match, "postfix match is experimental");
 
     if !visitor.features.never_patterns {
         if let Some(spans) = spans.get(&sym::never_patterns) {
@@ -607,13 +608,13 @@ pub fn check_crate(krate: &ast::Crate, sess: &Session, features: &Features) {
         };
     }
 
+    gate_all_legacy_dont_use!(box_patterns, "box pattern syntax is experimental");
     gate_all_legacy_dont_use!(trait_alias, "trait aliases are experimental");
     // Despite being a new feature, `where T: Trait<Assoc(): Sized>`, which is RTN syntax now,
     // used to be gated under associated_type_bounds, which are right above, so RTN needs to
     // be too.
     gate_all_legacy_dont_use!(return_type_notation, "return type notation is experimental");
     gate_all_legacy_dont_use!(decl_macro, "`macro` is experimental");
-    gate_all_legacy_dont_use!(box_patterns, "box pattern syntax is experimental");
     gate_all_legacy_dont_use!(
         exclusive_range_pattern,
         "exclusive range pattern syntax is experimental"
diff --git a/compiler/rustc_ast_pretty/src/pprust/state.rs b/compiler/rustc_ast_pretty/src/pprust/state.rs
index c50878e32a4..a70daf1b644 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state.rs
@@ -1626,6 +1626,12 @@ impl<'a> State<'a> {
                 self.word("box ");
                 self.print_pat(inner);
             }
+            PatKind::Deref(inner) => {
+                self.word("deref!");
+                self.popen();
+                self.print_pat(inner);
+                self.pclose();
+            }
             PatKind::Ref(inner, mutbl) => {
                 self.word("&");
                 if mutbl.is_mut() {
diff --git a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
index 433ef03b6e5..8bd8b6ac144 100644
--- a/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
+++ b/compiler/rustc_ast_pretty/src/pprust/state/expr.rs
@@ -1,6 +1,6 @@
 use crate::pp::Breaks::Inconsistent;
 use crate::pprust::state::{AnnNode, PrintState, State, INDENT_UNIT};
-use ast::ForLoopKind;
+use ast::{ForLoopKind, MatchKind};
 use itertools::{Itertools, Position};
 use rustc_ast::ptr::P;
 use rustc_ast::token;
@@ -589,12 +589,22 @@ impl<'a> State<'a> {
                 self.word_nbsp("loop");
                 self.print_block_with_attrs(blk, attrs);
             }
-            ast::ExprKind::Match(expr, arms) => {
+            ast::ExprKind::Match(expr, arms, match_kind) => {
                 self.cbox(0);
                 self.ibox(0);
-                self.word_nbsp("match");
-                self.print_expr_as_cond(expr);
-                self.space();
+
+                match match_kind {
+                    MatchKind::Prefix => {
+                        self.word_nbsp("match");
+                        self.print_expr_as_cond(expr);
+                        self.space();
+                    }
+                    MatchKind::Postfix => {
+                        self.print_expr_as_cond(expr);
+                        self.word_nbsp(".match");
+                    }
+                }
+
                 self.bopen();
                 self.print_inner_attributes_no_trailing_hardbreak(attrs);
                 for arm in arms {
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 0109f188772..aa98d060f5f 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -716,7 +716,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 .copied()
                 .find_map(find_fn_kind_from_did),
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => tcx
-                .explicit_item_bounds(def_id)
+                .explicit_item_super_predicates(def_id)
                 .iter_instantiated_copied(tcx, args)
                 .find_map(|(clause, span)| find_fn_kind_from_did((clause, span))),
             ty::Closure(_, args) => match args.as_closure().kind() {
diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
index bea9be24028..d5875a226fe 100644
--- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
@@ -192,6 +192,11 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                         .find(|ur_vid| self.eval_equal(vid, **ur_vid))
                         .and_then(|ur_vid| self.definitions[*ur_vid].external_name)
                         .unwrap_or(infcx.tcx.lifetimes.re_erased),
+                    ty::RePlaceholder(_) => ty::Region::new_error_with_message(
+                        infcx.tcx,
+                        concrete_type.span,
+                        "hidden type contains placeholders, we don't support higher kinded opaques yet",
+                    ),
                     _ => region,
                 });
             debug!(?universal_concrete_type);
@@ -434,10 +439,6 @@ fn check_opaque_type_parameter_valid(
     // Only check the parent generics, which will ignore any of the
     // duplicated lifetime args that come from reifying late-bounds.
     for (i, arg) in opaque_type_key.args.iter().take(parent_generics.count()).enumerate() {
-        if let Err(guar) = arg.error_reported() {
-            return Err(guar);
-        }
-
         let arg_is_param = match arg.unpack() {
             GenericArgKind::Type(ty) => matches!(ty.kind(), ty::Param(_)),
             GenericArgKind::Lifetime(lt) if is_ty_alias => {
diff --git a/compiler/rustc_builtin_macros/src/assert/context.rs b/compiler/rustc_builtin_macros/src/assert/context.rs
index 56c56b2704b..92efeab08eb 100644
--- a/compiler/rustc_builtin_macros/src/assert/context.rs
+++ b/compiler/rustc_builtin_macros/src/assert/context.rs
@@ -245,7 +245,7 @@ impl<'cx, 'a> Context<'cx, 'a> {
             ExprKind::Let(_, local_expr, _, _) => {
                 self.manage_cond_expr(local_expr);
             }
-            ExprKind::Match(local_expr, _) => {
+            ExprKind::Match(local_expr, ..) => {
                 self.manage_cond_expr(local_expr);
             }
             ExprKind::MethodCall(call) => {
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
index 6eccd67f8af..60dbdf8b544 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
@@ -132,7 +132,7 @@ fn cs_partial_cmp(
                 // Reference: https://github.com/rust-lang/rust/pull/103659#issuecomment-1328126354
 
                 if !tag_then_data
-                    && let ExprKind::Match(_, arms) = &mut expr1.kind
+                    && let ExprKind::Match(_, arms, _) = &mut expr1.kind
                     && let Some(last) = arms.last_mut()
                     && let PatKind::Wild = last.pat.kind
                 {
diff --git a/compiler/rustc_builtin_macros/src/deriving/debug.rs b/compiler/rustc_builtin_macros/src/deriving/debug.rs
index b11a1b6cda1..108c1078eaa 100644
--- a/compiler/rustc_builtin_macros/src/deriving/debug.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/debug.rs
@@ -2,8 +2,7 @@ use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::path_std;
 
-use ast::EnumDef;
-use rustc_ast::{self as ast, MetaItem};
+use rustc_ast::{self as ast, EnumDef, MetaItem};
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{sym, Ident, Symbol};
 use rustc_span::Span;
diff --git a/compiler/rustc_builtin_macros/src/lib.rs b/compiler/rustc_builtin_macros/src/lib.rs
index f344dbcd10c..554dac0852f 100644
--- a/compiler/rustc_builtin_macros/src/lib.rs
+++ b/compiler/rustc_builtin_macros/src/lib.rs
@@ -49,7 +49,6 @@ mod log_syntax;
 mod source_util;
 mod test;
 mod trace_macros;
-mod type_ascribe;
 mod util;
 
 pub mod asm;
@@ -99,7 +98,6 @@ pub fn register_builtin_macros(resolver: &mut dyn ResolverExpand) {
         std_panic: edition_panic::expand_panic,
         stringify: source_util::expand_stringify,
         trace_macros: trace_macros::expand_trace_macros,
-        type_ascribe: type_ascribe::expand_type_ascribe,
         unreachable: edition_panic::expand_unreachable,
         // tidy-alphabetical-end
     }
diff --git a/compiler/rustc_builtin_macros/src/type_ascribe.rs b/compiler/rustc_builtin_macros/src/type_ascribe.rs
deleted file mode 100644
index f3e66ffc759..00000000000
--- a/compiler/rustc_builtin_macros/src/type_ascribe.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-use rustc_ast::ptr::P;
-use rustc_ast::tokenstream::TokenStream;
-use rustc_ast::{token, Expr, ExprKind, Ty};
-use rustc_errors::PResult;
-use rustc_expand::base::{DummyResult, ExpandResult, ExtCtxt, MacEager, MacroExpanderResult};
-use rustc_span::Span;
-
-pub fn expand_type_ascribe(
-    cx: &mut ExtCtxt<'_>,
-    span: Span,
-    tts: TokenStream,
-) -> MacroExpanderResult<'static> {
-    let (expr, ty) = match parse_ascribe(cx, tts) {
-        Ok(parsed) => parsed,
-        Err(err) => {
-            let guar = err.emit();
-            return ExpandResult::Ready(DummyResult::any(span, guar));
-        }
-    };
-
-    let asc_expr = cx.expr(span, ExprKind::Type(expr, ty));
-
-    ExpandResult::Ready(MacEager::expr(asc_expr))
-}
-
-fn parse_ascribe<'a>(cx: &mut ExtCtxt<'a>, stream: TokenStream) -> PResult<'a, (P<Expr>, P<Ty>)> {
-    let mut parser = cx.new_parser_from_tts(stream);
-
-    let expr = parser.parse_expr()?;
-    parser.expect(&token::Comma)?;
-
-    let ty = parser.parse_ty()?;
-
-    Ok((expr, ty))
-}
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
index 133084b7c12..54f4bc06340 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs
@@ -85,14 +85,6 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
 
         let bx = self;
 
-        match coverage.kind {
-            // Marker statements have no effect during codegen,
-            // so return early and don't create `func_coverage`.
-            CoverageKind::SpanMarker | CoverageKind::BlockMarker { .. } => return,
-            // Match exhaustively to ensure that newly-added kinds are classified correctly.
-            CoverageKind::CounterIncrement { .. } | CoverageKind::ExpressionUsed { .. } => {}
-        }
-
         let Some(function_coverage_info) =
             bx.tcx.instance_mir(instance.def).function_coverage_info.as_deref()
         else {
@@ -109,7 +101,7 @@ impl<'tcx> CoverageInfoBuilderMethods<'tcx> for Builder<'_, '_, 'tcx> {
         let Coverage { kind } = coverage;
         match *kind {
             CoverageKind::SpanMarker | CoverageKind::BlockMarker { .. } => unreachable!(
-                "unexpected marker statement {kind:?} should have caused an early return"
+                "marker statement {kind:?} should have been removed by CleanupPostBorrowck"
             ),
             CoverageKind::CounterIncrement { id } => {
                 func_coverage.mark_counter_id_seen(id);
diff --git a/compiler/rustc_codegen_ssa/src/back/command.rs b/compiler/rustc_codegen_ssa/src/back/command.rs
index 9b0ba34135c..3a89be89951 100644
--- a/compiler/rustc_codegen_ssa/src/back/command.rs
+++ b/compiler/rustc_codegen_ssa/src/back/command.rs
@@ -100,12 +100,6 @@ impl Command {
             Program::Lld(ref p, flavor) => {
                 let mut c = process::Command::new(p);
                 c.arg("-flavor").arg(flavor.as_str());
-                if let LldFlavor::Wasm = flavor {
-                    // LLVM expects host-specific formatting for @file
-                    // arguments, but we always generate posix formatted files
-                    // at this time. Indicate as such.
-                    c.arg("--rsp-quoting=posix");
-                }
                 c
             }
         };
diff --git a/compiler/rustc_codegen_ssa/src/back/link.rs b/compiler/rustc_codegen_ssa/src/back/link.rs
index f5e8d5fc92a..c8b8594c0dd 100644
--- a/compiler/rustc_codegen_ssa/src/back/link.rs
+++ b/compiler/rustc_codegen_ssa/src/back/link.rs
@@ -785,7 +785,7 @@ fn link_natively<'a>(
     let mut i = 0;
     loop {
         i += 1;
-        prog = sess.time("run_linker", || exec_linker(sess, &cmd, out_filename, tmpdir));
+        prog = sess.time("run_linker", || exec_linker(sess, &cmd, out_filename, flavor, tmpdir));
         let Ok(ref output) = prog else {
             break;
         };
@@ -1576,6 +1576,7 @@ fn exec_linker(
     sess: &Session,
     cmd: &Command,
     out_filename: &Path,
+    flavor: LinkerFlavor,
     tmpdir: &Path,
 ) -> io::Result<Output> {
     // When attempting to spawn the linker we run a risk of blowing out the
@@ -1584,9 +1585,9 @@ fn exec_linker(
     //
     // Here we attempt to handle errors from the OS saying "your list of
     // arguments is too big" by reinvoking the linker again with an `@`-file
-    // that contains all the arguments. The theory is that this is then
-    // accepted on all linkers and the linker will read all its options out of
-    // there instead of looking at the command line.
+    // that contains all the arguments (aka 'response' files).
+    // The theory is that this is then accepted on all linkers and the linker
+    // will read all its options out of there instead of looking at the command line.
     if !cmd.very_likely_to_exceed_some_spawn_limit() {
         match cmd.command().stdout(Stdio::piped()).stderr(Stdio::piped()).spawn() {
             Ok(child) => {
@@ -1606,8 +1607,12 @@ fn exec_linker(
     let mut args = String::new();
     for arg in cmd2.take_args() {
         args.push_str(
-            &Escape { arg: arg.to_str().unwrap(), is_like_msvc: sess.target.is_like_msvc }
-                .to_string(),
+            &Escape {
+                arg: arg.to_str().unwrap(),
+                // LLD also uses MSVC-like parsing for @-files by default when running on windows hosts
+                is_like_msvc: sess.target.is_like_msvc || (cfg!(windows) && flavor.uses_lld()),
+            }
+            .to_string(),
         );
         args.push('\n');
     }
diff --git a/compiler/rustc_codegen_ssa/src/traits/backend.rs b/compiler/rustc_codegen_ssa/src/traits/backend.rs
index e6d42c596d2..e8b9490d401 100644
--- a/compiler/rustc_codegen_ssa/src/traits/backend.rs
+++ b/compiler/rustc_codegen_ssa/src/traits/backend.rs
@@ -21,7 +21,6 @@ use rustc_session::{
 };
 use rustc_span::symbol::Symbol;
 use rustc_target::abi::call::FnAbi;
-use rustc_target::spec::Target;
 
 use std::fmt;
 
@@ -70,12 +69,6 @@ pub trait CodegenBackend {
     fn print_passes(&self) {}
     fn print_version(&self) {}
 
-    /// If this plugin provides additional builtin targets, provide the one enabled by the options here.
-    /// Be careful: this is called *before* init() is called.
-    fn target_override(&self, _opts: &config::Options) -> Option<Target> {
-        None
-    }
-
     /// The metadata loader used to load rlib and dylib metadata.
     ///
     /// Alternative codegen backends may want to use different rlib or dylib formats than the
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index a6ca4b2e0de..9b1d9cf932b 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -1159,11 +1159,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         };
 
         // Side-step AllocRef and directly access the underlying bytes more efficiently.
-        // (We are staying inside the bounds here so all is good.)
+        // (We are staying inside the bounds here and all bytes do get overwritten so all is good.)
         let alloc_id = alloc_ref.alloc_id;
         let bytes = alloc_ref
             .alloc
-            .get_bytes_mut(&alloc_ref.tcx, alloc_ref.range)
+            .get_bytes_unchecked_for_overwrite(&alloc_ref.tcx, alloc_ref.range)
             .map_err(move |e| e.to_interp_error(alloc_id))?;
         // `zip` would stop when the first iterator ends; we want to definitely
         // cover all of `bytes`.
@@ -1184,6 +1184,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         self.mem_copy_repeatedly(src, dest, size, 1, nonoverlapping)
     }
 
+    /// Performs `num_copies` many copies of `size` many bytes from `src` to `dest + i*size` (where
+    /// `i` is the index of the copy).
+    ///
+    /// Either `nonoverlapping` must be true or `num_copies` must be 1; doing repeated copies that
+    /// may overlap is not supported.
     pub fn mem_copy_repeatedly(
         &mut self,
         src: Pointer<Option<M::Provenance>>,
@@ -1245,8 +1250,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             (dest_alloc_id, dest_prov),
             dest_range,
         )?;
+        // Yes we do overwrite all bytes in `dest_bytes`.
         let dest_bytes = dest_alloc
-            .get_bytes_mut_ptr(&tcx, dest_range)
+            .get_bytes_unchecked_for_overwrite_ptr(&tcx, dest_range)
             .map_err(|e| e.to_interp_error(dest_alloc_id))?
             .as_mut_ptr();
 
@@ -1280,6 +1286,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                     }
                 }
             }
+            if num_copies > 1 {
+                assert!(nonoverlapping, "multi-copy only supported in non-overlapping mode");
+            }
 
             let size_in_bytes = size.bytes_usize();
             // For particularly large arrays (where this is perf-sensitive) it's common that
@@ -1292,6 +1301,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
             } else if src_alloc_id == dest_alloc_id {
                 let mut dest_ptr = dest_bytes;
                 for _ in 0..num_copies {
+                    // Here we rely on `src` and `dest` being non-overlapping if there is more than
+                    // one copy.
                     ptr::copy(src_bytes, dest_ptr, size_in_bytes);
                     dest_ptr = dest_ptr.add(size_in_bytes);
                 }
diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index 68270dab284..4bc49f90607 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -4,6 +4,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
 use rustc_infer::traits::Reveal;
+use rustc_middle::mir::coverage::CoverageKind;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::visit::{NonUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
@@ -345,11 +346,21 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
                     self.fail(location, format!("explicit `{kind:?}` is forbidden"));
                 }
             }
+            StatementKind::Coverage(coverage) => {
+                let kind = &coverage.kind;
+                if self.mir_phase >= MirPhase::Analysis(AnalysisPhase::PostCleanup)
+                    && let CoverageKind::BlockMarker { .. } | CoverageKind::SpanMarker { .. } = kind
+                {
+                    self.fail(
+                        location,
+                        format!("{kind:?} should have been removed after analysis"),
+                    );
+                }
+            }
             StatementKind::Assign(..)
             | StatementKind::StorageLive(_)
             | StatementKind::StorageDead(_)
             | StatementKind::Intrinsic(_)
-            | StatementKind::Coverage(_)
             | StatementKind::ConstEvalCounter
             | StatementKind::PlaceMention(..)
             | StatementKind::Nop => {}
diff --git a/compiler/rustc_data_structures/src/sync.rs b/compiler/rustc_data_structures/src/sync.rs
index 32202ac3ede..eab6d8168ca 100644
--- a/compiler/rustc_data_structures/src/sync.rs
+++ b/compiler/rustc_data_structures/src/sync.rs
@@ -20,6 +20,7 @@
 //! | ----------------------- | ------------------- | ------------------------------- |
 //! | `Lrc<T>`                | `rc::Rc<T>`         | `sync::Arc<T>`                  |
 //! |` Weak<T>`               | `rc::Weak<T>`       | `sync::Weak<T>`                 |
+//! | `LRef<'a, T>` [^2]      | `&'a mut T`         | `&'a T`                         |
 //! |                         |                     |                                 |
 //! | `AtomicBool`            | `Cell<bool>`        | `atomic::AtomicBool`            |
 //! | `AtomicU32`             | `Cell<u32>`         | `atomic::AtomicU32`             |
@@ -38,7 +39,7 @@
 //! of a `RefCell`. This is appropriate when interior mutability is not
 //! required.
 //!
-//! [^2] `MTLockRef` is a typedef.
+//! [^2] `MTRef`, `MTLockRef` are type aliases.
 
 pub use crate::marker::*;
 use std::collections::HashMap;
@@ -208,7 +209,7 @@ cfg_match! {
 
         use std::cell::RefCell as InnerRwLock;
 
-        pub type MTLockRef<'a, T> = &'a mut MTLock<T>;
+        pub type LRef<'a, T> = &'a mut T;
 
         #[derive(Debug, Default)]
         pub struct MTLock<T>(T);
@@ -274,7 +275,7 @@ cfg_match! {
         pub use std::sync::Arc as Lrc;
         pub use std::sync::Weak as Weak;
 
-        pub type MTLockRef<'a, T> = &'a MTLock<T>;
+        pub type LRef<'a, T> = &'a T;
 
         #[derive(Debug, Default)]
         pub struct MTLock<T>(Lock<T>);
@@ -314,6 +315,8 @@ cfg_match! {
     }
 }
 
+pub type MTLockRef<'a, T> = LRef<'a, MTLock<T>>;
+
 #[derive(Default)]
 #[cfg_attr(parallel_compiler, repr(align(64)))]
 pub struct CacheAligned<T>(pub T);
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 938f9f0beaa..716e31080dd 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -890,7 +890,7 @@ pub fn version_at_macro_invocation(
         let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
         let opts = config::Options::default();
         let sysroot = filesearch::materialize_sysroot(opts.maybe_sysroot.clone());
-        let target = config::build_target_config(early_dcx, &opts, None, &sysroot);
+        let target = config::build_target_config(early_dcx, &opts, &sysroot);
 
         get_codegen_backend(early_dcx, &sysroot, backend_name, &target).print_version();
     }
@@ -1100,7 +1100,7 @@ pub fn describe_flag_categories(early_dcx: &EarlyDiagCtxt, matches: &Matches) ->
 
         let opts = config::Options::default();
         let sysroot = filesearch::materialize_sysroot(opts.maybe_sysroot.clone());
-        let target = config::build_target_config(early_dcx, &opts, None, &sysroot);
+        let target = config::build_target_config(early_dcx, &opts, &sysroot);
 
         get_codegen_backend(early_dcx, &sysroot, backend_name, &target).print_passes();
         return true;
diff --git a/compiler/rustc_expand/messages.ftl b/compiler/rustc_expand/messages.ftl
index 1f0488130b2..fdd1a87cae8 100644
--- a/compiler/rustc_expand/messages.ftl
+++ b/compiler/rustc_expand/messages.ftl
@@ -33,6 +33,9 @@ expand_duplicate_matcher_binding = duplicate matcher binding
 expand_expected_comma_in_list =
     expected token: `,`
 
+expand_expected_paren_or_brace =
+    expected `(` or `{"{"}`, found `{$token}`
+
 expand_explain_doc_comment_inner =
     inner doc comments expand to `#![doc = "..."]`, which is what this macro attempted to match
 
diff --git a/compiler/rustc_expand/src/build.rs b/compiler/rustc_expand/src/build.rs
index e71047f94fa..30559871b4e 100644
--- a/compiler/rustc_expand/src/build.rs
+++ b/compiler/rustc_expand/src/build.rs
@@ -1,6 +1,6 @@
 use crate::base::ExtCtxt;
 use rustc_ast::ptr::P;
-use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, PatKind, UnOp};
+use rustc_ast::{self as ast, AttrVec, BlockCheckMode, Expr, LocalKind, MatchKind, PatKind, UnOp};
 use rustc_ast::{attr, token, util::literal};
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
@@ -524,7 +524,7 @@ impl<'a> ExtCtxt<'a> {
     }
 
     pub fn expr_match(&self, span: Span, arg: P<ast::Expr>, arms: ThinVec<ast::Arm>) -> P<Expr> {
-        self.expr(span, ast::ExprKind::Match(arg, arms))
+        self.expr(span, ast::ExprKind::Match(arg, arms, MatchKind::Prefix))
     }
 
     pub fn expr_if(
diff --git a/compiler/rustc_expand/src/errors.rs b/compiler/rustc_expand/src/errors.rs
index fe901603c73..21ce5e1d81e 100644
--- a/compiler/rustc_expand/src/errors.rs
+++ b/compiler/rustc_expand/src/errors.rs
@@ -448,3 +448,11 @@ pub struct InvalidFragmentSpecifier {
     pub fragment: Ident,
     pub help: String,
 }
+
+#[derive(Diagnostic)]
+#[diag(expand_expected_paren_or_brace)]
+pub struct ExpectedParenOrBrace<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub token: Cow<'a, str>,
+}
diff --git a/compiler/rustc_expand/src/mbe/macro_parser.rs b/compiler/rustc_expand/src/mbe/macro_parser.rs
index ac5136539c3..a31be05ccc4 100644
--- a/compiler/rustc_expand/src/mbe/macro_parser.rs
+++ b/compiler/rustc_expand/src/mbe/macro_parser.rs
@@ -392,12 +392,7 @@ pub(super) fn count_metavar_decls(matcher: &[TokenTree]) -> usize {
 #[derive(Debug, Clone)]
 pub(crate) enum NamedMatch {
     MatchedSeq(Vec<NamedMatch>),
-
-    // A metavar match of type `tt`.
-    MatchedTokenTree(rustc_ast::tokenstream::TokenTree),
-
-    // A metavar match of any type other than `tt`.
-    MatchedNonterminal(Lrc<(Nonterminal, rustc_span::Span)>),
+    MatchedSingle(ParseNtResult<Lrc<(Nonterminal, Span)>>),
 }
 
 /// Performs a token equality check, ignoring syntax context (that is, an unhygienic comparison)
@@ -691,11 +686,11 @@ impl TtParser {
                             }
                             Ok(nt) => nt,
                         };
-                        let m = match nt {
-                            ParseNtResult::Nt(nt) => MatchedNonterminal(Lrc::new((nt, span))),
-                            ParseNtResult::Tt(tt) => MatchedTokenTree(tt),
-                        };
-                        mp.push_match(next_metavar, seq_depth, m);
+                        mp.push_match(
+                            next_metavar,
+                            seq_depth,
+                            MatchedSingle(nt.map_nt(|nt| (Lrc::new((nt, span))))),
+                        );
                         mp.idx += 1;
                     } else {
                         unreachable!()
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index 3f29d7f7465..7099f1b0d35 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -5,7 +5,7 @@ use crate::mbe;
 use crate::mbe::diagnostics::{annotate_doc_comment, parse_failure_msg};
 use crate::mbe::macro_check;
 use crate::mbe::macro_parser::{Error, ErrorReported, Failure, Success, TtParser};
-use crate::mbe::macro_parser::{MatchedSeq, MatchedTokenTree, MatcherLoc};
+use crate::mbe::macro_parser::{MatcherLoc, NamedMatch::*};
 use crate::mbe::transcribe::transcribe;
 
 use ast::token::IdentIsRaw;
@@ -22,7 +22,7 @@ use rustc_lint_defs::builtin::{
     RUST_2021_INCOMPATIBLE_OR_PATTERNS, SEMICOLON_IN_EXPRESSIONS_FROM_MACROS,
 };
 use rustc_lint_defs::BuiltinLintDiag;
-use rustc_parse::parser::{Parser, Recovery};
+use rustc_parse::parser::{ParseNtResult, Parser, Recovery};
 use rustc_session::parse::ParseSess;
 use rustc_session::Session;
 use rustc_span::edition::Edition;
@@ -479,7 +479,7 @@ pub fn compile_declarative_macro(
         MatchedSeq(s) => s
             .iter()
             .map(|m| {
-                if let MatchedTokenTree(tt) = m {
+                if let MatchedSingle(ParseNtResult::Tt(tt)) = m {
                     let tt = mbe::quoted::parse(
                         &TokenStream::new(vec![tt.clone()]),
                         true,
@@ -505,7 +505,7 @@ pub fn compile_declarative_macro(
         MatchedSeq(s) => s
             .iter()
             .map(|m| {
-                if let MatchedTokenTree(tt) = m {
+                if let MatchedSingle(ParseNtResult::Tt(tt)) = m {
                     return mbe::quoted::parse(
                         &TokenStream::new(vec![tt.clone()]),
                         false,
diff --git a/compiler/rustc_expand/src/mbe/quoted.rs b/compiler/rustc_expand/src/mbe/quoted.rs
index 5fd3716743b..06c1612ddba 100644
--- a/compiler/rustc_expand/src/mbe/quoted.rs
+++ b/compiler/rustc_expand/src/mbe/quoted.rs
@@ -194,9 +194,11 @@ fn parse_tree<'a>(
                             }
                             Delimiter::Parenthesis => {}
                             _ => {
-                                let tok = pprust::token_kind_to_string(&token::OpenDelim(delim));
-                                let msg = format!("expected `(` or `{{`, found `{tok}`");
-                                sess.dcx().span_err(delim_span.entire(), msg);
+                                let token = pprust::token_kind_to_string(&token::OpenDelim(delim));
+                                sess.dcx().emit_err(errors::ExpectedParenOrBrace {
+                                    span: delim_span.entire(),
+                                    token,
+                                });
                             }
                         }
                     }
diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index 8fcd468e34b..dad83984c8b 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -3,14 +3,14 @@ use crate::errors::{
     CountRepetitionMisplaced, MetaVarExprUnrecognizedVar, MetaVarsDifSeqMatchers, MustRepeatOnce,
     NoSyntaxVarsExprRepeat, VarStillRepeating,
 };
-use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, MatchedTokenTree, NamedMatch};
+use crate::mbe::macro_parser::{NamedMatch, NamedMatch::*};
 use crate::mbe::{self, KleeneOp, MetaVarExpr};
 use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::token::{self, Delimiter, Token, TokenKind};
 use rustc_ast::tokenstream::{DelimSpacing, DelimSpan, Spacing, TokenStream, TokenTree};
 use rustc_data_structures::fx::FxHashMap;
-use rustc_errors::Diag;
-use rustc_errors::{pluralize, PResult};
+use rustc_errors::{pluralize, Diag, PResult};
+use rustc_parse::parser::ParseNtResult;
 use rustc_span::hygiene::{LocalExpnId, Transparency};
 use rustc_span::symbol::{sym, Ident, MacroRulesNormalizedIdent};
 use rustc_span::{with_metavar_spans, Span, SyntaxContext};
@@ -250,26 +250,25 @@ pub(super) fn transcribe<'a>(
                 // the meta-var.
                 let ident = MacroRulesNormalizedIdent::new(original_ident);
                 if let Some(cur_matched) = lookup_cur_matched(ident, interp, &repeats) {
-                    match cur_matched {
-                        MatchedTokenTree(tt) => {
+                    let tt = match cur_matched {
+                        MatchedSingle(ParseNtResult::Tt(tt)) => {
                             // `tt`s are emitted into the output stream directly as "raw tokens",
                             // without wrapping them into groups.
-                            let tt = maybe_use_metavar_location(cx, &stack, sp, tt, &mut marker);
-                            result.push(tt);
+                            maybe_use_metavar_location(cx, &stack, sp, tt, &mut marker)
                         }
-                        MatchedNonterminal(nt) => {
+                        MatchedSingle(ParseNtResult::Nt(nt)) => {
                             // Other variables are emitted into the output stream as groups with
                             // `Delimiter::Invisible` to maintain parsing priorities.
                             // `Interpolated` is currently used for such groups in rustc parser.
                             marker.visit_span(&mut sp);
-                            result
-                                .push(TokenTree::token_alone(token::Interpolated(nt.clone()), sp));
+                            TokenTree::token_alone(token::Interpolated(nt.clone()), sp)
                         }
                         MatchedSeq(..) => {
                             // We were unable to descend far enough. This is an error.
                             return Err(cx.dcx().create_err(VarStillRepeating { span: sp, ident }));
                         }
-                    }
+                    };
+                    result.push(tt)
                 } else {
                     // If we aren't able to match the meta-var, we push it back into the result but
                     // with modified syntax context. (I believe this supports nested macros).
@@ -424,7 +423,7 @@ fn lookup_cur_matched<'a>(
     interpolations.get(&ident).map(|mut matched| {
         for &(idx, _) in repeats {
             match matched {
-                MatchedTokenTree(_) | MatchedNonterminal(_) => break,
+                MatchedSingle(_) => break,
                 MatchedSeq(ads) => matched = ads.get(idx).unwrap(),
             }
         }
@@ -514,7 +513,7 @@ fn lockstep_iter_size(
             let name = MacroRulesNormalizedIdent::new(*name);
             match lookup_cur_matched(name, interpolations, repeats) {
                 Some(matched) => match matched {
-                    MatchedTokenTree(_) | MatchedNonterminal(_) => LockstepIterSize::Unconstrained,
+                    MatchedSingle(_) => LockstepIterSize::Unconstrained,
                     MatchedSeq(ads) => LockstepIterSize::Constraint(ads.len(), name),
                 },
                 _ => LockstepIterSize::Unconstrained,
@@ -557,7 +556,7 @@ fn count_repetitions<'a>(
     // (or at the top-level of `matched` if no depth is given).
     fn count<'a>(depth_curr: usize, depth_max: usize, matched: &NamedMatch) -> PResult<'a, usize> {
         match matched {
-            MatchedTokenTree(_) | MatchedNonterminal(_) => Ok(1),
+            MatchedSingle(_) => Ok(1),
             MatchedSeq(named_matches) => {
                 if depth_curr == depth_max {
                     Ok(named_matches.len())
@@ -571,7 +570,7 @@ fn count_repetitions<'a>(
     /// Maximum depth
     fn depth(counter: usize, matched: &NamedMatch) -> usize {
         match matched {
-            MatchedTokenTree(_) | MatchedNonterminal(_) => counter,
+            MatchedSingle(_) => counter,
             MatchedSeq(named_matches) => {
                 let rslt = counter + 1;
                 if let Some(elem) = named_matches.first() { depth(rslt, elem) } else { rslt }
@@ -599,7 +598,7 @@ fn count_repetitions<'a>(
         }
     }
 
-    if let MatchedTokenTree(_) | MatchedNonterminal(_) = matched {
+    if let MatchedSingle(_) = matched {
         return Err(cx.dcx().create_err(CountRepetitionMisplaced { span: sp.entire() }));
     }
 
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index d4d7833cb21..22cf50fce7f 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -597,9 +597,12 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
     ),
 
     rustc_attr!(
-        rustc_never_type_mode, Normal, template!(NameValueStr: "fallback_to_unit|fallback_to_niko|fallback_to_never|no_fallback"), ErrorFollowing,
+        rustc_never_type_options,
+        Normal,
+        template!(List: r#"/*opt*/ fallback = "unit|niko|never|no""#),
+        ErrorFollowing,
         EncodeCrossCrate::No,
-        "`rustc_never_type_fallback` is used to experiment with never type fallback and work on \
+        "`rustc_never_type_options` is used to experiment with never type fallback and work on \
          never type stabilization, and will never be stable"
     ),
 
diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
index a3b13c4d907..8d72f4924d6 100644
--- a/compiler/rustc_feature/src/unstable.rs
+++ b/compiler/rustc_feature/src/unstable.rs
@@ -436,6 +436,8 @@ declare_features! (
     (unstable, deprecated_safe, "1.61.0", Some(94978)),
     /// Allows having using `suggestion` in the `#[deprecated]` attribute.
     (unstable, deprecated_suggestion, "1.61.0", Some(94785)),
+    /// Allows deref patterns.
+    (incomplete, deref_patterns, "CURRENT_RUSTC_VERSION", Some(87121)),
     /// Controls errors in trait implementations.
     (unstable, do_not_recommend, "1.67.0", Some(51992)),
     /// Tells rustdoc to automatically generate `#[doc(cfg(...))]`.
@@ -557,6 +559,8 @@ declare_features! (
     (unstable, offset_of_nested, "1.77.0", Some(120140)),
     /// Allows using `#[optimize(X)]`.
     (unstable, optimize_attribute, "1.34.0", Some(54882)),
+    /// Allows postfix match `expr.match { ... }`
+    (unstable, postfix_match, "CURRENT_RUSTC_VERSION", Some(121618)),
     /// Allows macro attributes on expressions, statements and non-inline modules.
     (unstable, proc_macro_hygiene, "1.30.0", Some(54727)),
     /// Allows `&raw const $place_expr` and `&raw mut $place_expr` expressions.
diff --git a/compiler/rustc_hir/src/def.rs b/compiler/rustc_hir/src/def.rs
index 1810193c16b..e8cecb1930f 100644
--- a/compiler/rustc_hir/src/def.rs
+++ b/compiler/rustc_hir/src/def.rs
@@ -810,6 +810,8 @@ pub enum LifetimeRes {
         param: NodeId,
         /// Id of the introducing place. See `Param`.
         binder: NodeId,
+        /// Kind of elided lifetime
+        kind: hir::MissingLifetimeKind,
     },
     /// This variant is used for anonymous lifetimes that we did not resolve during
     /// late resolution. Those lifetimes will be inferred by typechecking.
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index ca5d2930e82..430fdf2aa93 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -456,6 +456,18 @@ impl GenericBound<'_> {
 
 pub type GenericBounds<'hir> = &'hir [GenericBound<'hir>];
 
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable_Generic, Debug)]
+pub enum MissingLifetimeKind {
+    /// An explicit `'_`.
+    Underscore,
+    /// An elided lifetime `&' ty`.
+    Ampersand,
+    /// An elided lifetime in brackets with written brackets.
+    Comma,
+    /// An elided lifetime with elided brackets.
+    Brackets,
+}
+
 #[derive(Copy, Clone, Debug, HashStable_Generic)]
 pub enum LifetimeParamKind {
     // Indicates that the lifetime definition was explicitly declared (e.g., in
@@ -464,7 +476,7 @@ pub enum LifetimeParamKind {
 
     // Indication that the lifetime was elided (e.g., in both cases in
     // `fn foo(x: &u8) -> &'_ u8 { x }`).
-    Elided,
+    Elided(MissingLifetimeKind),
 
     // Indication that the lifetime name was somehow in error.
     Error,
@@ -512,7 +524,7 @@ impl<'hir> GenericParam<'hir> {
     ///
     /// See `lifetime_to_generic_param` in `rustc_ast_lowering` for more information.
     pub fn is_elided_lifetime(&self) -> bool {
-        matches!(self.kind, GenericParamKind::Lifetime { kind: LifetimeParamKind::Elided })
+        matches!(self.kind, GenericParamKind::Lifetime { kind: LifetimeParamKind::Elided(_) })
     }
 }
 
@@ -1003,7 +1015,7 @@ impl<'hir> Pat<'hir> {
         use PatKind::*;
         match self.kind {
             Wild | Never | Lit(_) | Range(..) | Binding(.., None) | Path(_) | Err(_) => true,
-            Box(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_short_(it),
+            Box(s) | Deref(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_short_(it),
             Struct(_, fields, _) => fields.iter().all(|field| field.pat.walk_short_(it)),
             TupleStruct(_, s, _) | Tuple(s, _) | Or(s) => s.iter().all(|p| p.walk_short_(it)),
             Slice(before, slice, after) => {
@@ -1030,7 +1042,7 @@ impl<'hir> Pat<'hir> {
         use PatKind::*;
         match self.kind {
             Wild | Never | Lit(_) | Range(..) | Binding(.., None) | Path(_) | Err(_) => {}
-            Box(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_(it),
+            Box(s) | Deref(s) | Ref(s, _) | Binding(.., Some(s)) => s.walk_(it),
             Struct(_, fields, _) => fields.iter().for_each(|field| field.pat.walk_(it)),
             TupleStruct(_, s, _) | Tuple(s, _) | Or(s) => s.iter().for_each(|p| p.walk_(it)),
             Slice(before, slice, after) => {
@@ -1173,6 +1185,9 @@ pub enum PatKind<'hir> {
     /// A `box` pattern.
     Box(&'hir Pat<'hir>),
 
+    /// A `deref` pattern (currently `deref!()` macro-based syntax).
+    Deref(&'hir Pat<'hir>),
+
     /// A reference pattern (e.g., `&mut (a, b)`).
     Ref(&'hir Pat<'hir>, Mutability),
 
@@ -1259,7 +1274,7 @@ pub struct Arm<'hir> {
 /// In an `if let`, imagine it as `if (let <pat> = <expr>) { ... }`; in a let-else, it is part of
 /// the desugaring to if-let. Only let-else supports the type annotation at present.
 #[derive(Debug, Clone, Copy, HashStable_Generic)]
-pub struct Let<'hir> {
+pub struct LetExpr<'hir> {
     pub span: Span,
     pub pat: &'hir Pat<'hir>,
     pub ty: Option<&'hir Ty<'hir>>,
@@ -1852,7 +1867,7 @@ pub enum ExprKind<'hir> {
     ///
     /// These are not `Local` and only occur as expressions.
     /// The `let Some(x) = foo()` in `if let Some(x) = foo()` is an example of `Let(..)`.
-    Let(&'hir Let<'hir>),
+    Let(&'hir LetExpr<'hir>),
     /// An `if` block, with an optional else block.
     ///
     /// I.e., `if <expr> { <expr> } else { <expr> }`.
@@ -2004,6 +2019,8 @@ pub enum LocalSource {
 pub enum MatchSource {
     /// A `match _ { .. }`.
     Normal,
+    /// A `expr.match { .. }`.
+    Postfix,
     /// A desugared `for _ in _ { .. }` loop.
     ForLoopDesugar,
     /// A desugared `?` operator.
@@ -2020,6 +2037,7 @@ impl MatchSource {
         use MatchSource::*;
         match self {
             Normal => "match",
+            Postfix => ".match",
             ForLoopDesugar => "for",
             TryDesugar(_) => "?",
             AwaitDesugar => ".await",
diff --git a/compiler/rustc_hir/src/intravisit.rs b/compiler/rustc_hir/src/intravisit.rs
index 186bb234a45..468c7fd5c73 100644
--- a/compiler/rustc_hir/src/intravisit.rs
+++ b/compiler/rustc_hir/src/intravisit.rs
@@ -660,7 +660,9 @@ pub fn walk_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v Pat<'v>) -> V:
         PatKind::Tuple(tuple_elements, _) => {
             walk_list!(visitor, visit_pat, tuple_elements);
         }
-        PatKind::Box(ref subpattern) | PatKind::Ref(ref subpattern, _) => {
+        PatKind::Box(ref subpattern)
+        | PatKind::Deref(ref subpattern)
+        | PatKind::Ref(ref subpattern, _) => {
             try_visit!(visitor.visit_pat(subpattern));
         }
         PatKind::Binding(_, _hir_id, ident, ref optional_subpattern) => {
@@ -753,7 +755,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
         ExprKind::DropTemps(ref subexpression) => {
             try_visit!(visitor.visit_expr(subexpression));
         }
-        ExprKind::Let(Let { span: _, pat, ty, init, is_recovered: _ }) => {
+        ExprKind::Let(LetExpr { span: _, pat, ty, init, is_recovered: _ }) => {
             // match the visit order in walk_local
             try_visit!(visitor.visit_expr(init));
             try_visit!(visitor.visit_pat(pat));
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index 5118bf5c3b7..dbf86f5cf74 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -214,6 +214,7 @@ language_item_table! {
     FnOnceOutput,            sym::fn_once_output,      fn_once_output,             Target::AssocTy,        GenericRequirement::None;
 
     Iterator,                sym::iterator,            iterator_trait,             Target::Trait,          GenericRequirement::Exact(0);
+    FusedIterator,           sym::fused_iterator,      fused_iterator_trait,       Target::Trait,          GenericRequirement::Exact(0);
     Future,                  sym::future_trait,        future_trait,               Target::Trait,          GenericRequirement::Exact(0);
     AsyncIterator,           sym::async_iterator,      async_iterator_trait,       Target::Trait,          GenericRequirement::Exact(0);
 
diff --git a/compiler/rustc_hir_analysis/src/astconv/bounds.rs b/compiler/rustc_hir_analysis/src/astconv/bounds.rs
index 3067e2d0b71..7a5cb6e9d6f 100644
--- a/compiler/rustc_hir_analysis/src/astconv/bounds.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/bounds.rs
@@ -565,7 +565,7 @@ fn check_assoc_const_binding_type<'tcx>(
     let mut guar = ty.visit_with(&mut collector).break_value();
 
     let ty_note = ty
-        .make_suggestable(tcx, false)
+        .make_suggestable(tcx, false, None)
         .map(|ty| crate::errors::TyOfAssocConstBindingNote { assoc_const, ty });
 
     let enclosing_item_owner_id = tcx
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
index ec9e928ce59..d2fdff6177e 100644
--- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
+++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -1305,7 +1305,7 @@ fn compare_number_of_generics<'tcx>(
                     .iter()
                     .filter(|p| match p.kind {
                         hir::GenericParamKind::Lifetime {
-                            kind: hir::LifetimeParamKind::Elided,
+                            kind: hir::LifetimeParamKind::Elided(_),
                         } => {
                             // A fn can have an arbitrary number of extra elided lifetimes for the
                             // same signature.
diff --git a/compiler/rustc_hir_analysis/src/check/mod.rs b/compiler/rustc_hir_analysis/src/check/mod.rs
index 4c4ff28808e..8760901b71b 100644
--- a/compiler/rustc_hir_analysis/src/check/mod.rs
+++ b/compiler/rustc_hir_analysis/src/check/mod.rs
@@ -431,7 +431,7 @@ fn fn_sig_suggestion<'tcx>(
 
     let asyncness = if tcx.asyncness(assoc.def_id).is_async() {
         output = if let ty::Alias(_, alias_ty) = *output.kind() {
-            tcx.explicit_item_bounds(alias_ty.def_id)
+            tcx.explicit_item_super_predicates(alias_ty.def_id)
                 .iter_instantiated_copied(tcx, alias_ty.args)
                 .find_map(|(bound, _)| bound.as_projection_clause()?.no_bound_vars()?.term.ty())
                 .unwrap_or_else(|| {
diff --git a/compiler/rustc_hir_analysis/src/check/region.rs b/compiler/rustc_hir_analysis/src/check/region.rs
index 3c26729eff8..eb31e1546cf 100644
--- a/compiler/rustc_hir_analysis/src/check/region.rs
+++ b/compiler/rustc_hir_analysis/src/check/region.rs
@@ -668,7 +668,7 @@ fn resolve_local<'tcx>(
             | PatKind::TupleStruct(_, subpats, _)
             | PatKind::Tuple(subpats, _) => subpats.iter().any(|p| is_binding_pat(p)),
 
-            PatKind::Box(subpat) => is_binding_pat(subpat),
+            PatKind::Box(subpat) | PatKind::Deref(subpat) => is_binding_pat(subpat),
 
             PatKind::Ref(_, _)
             | PatKind::Binding(hir::BindingAnnotation(hir::ByRef::No, _), ..)
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 5cd6862786b..6c3f99ccc12 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -61,6 +61,9 @@ pub fn provide(providers: &mut Providers) {
         type_alias_is_lazy: type_of::type_alias_is_lazy,
         item_bounds: item_bounds::item_bounds,
         explicit_item_bounds: item_bounds::explicit_item_bounds,
+        item_super_predicates: item_bounds::item_super_predicates,
+        explicit_item_super_predicates: item_bounds::explicit_item_super_predicates,
+        item_non_self_assumptions: item_bounds::item_non_self_assumptions,
         generics_of: generics_of::generics_of,
         predicates_of: predicates_of::predicates_of,
         predicates_defined_on,
@@ -633,7 +636,9 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
             tcx.ensure().generics_of(def_id);
             tcx.ensure().predicates_of(def_id);
             tcx.ensure().explicit_item_bounds(def_id);
+            tcx.ensure().explicit_item_super_predicates(def_id);
             tcx.ensure().item_bounds(def_id);
+            tcx.ensure().item_super_predicates(def_id);
         }
 
         hir::ItemKind::TyAlias(..) => {
@@ -689,6 +694,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
 
         hir::TraitItemKind::Type(_, Some(_)) => {
             tcx.ensure().item_bounds(def_id);
+            tcx.ensure().item_super_predicates(def_id);
             tcx.ensure().type_of(def_id);
             // Account for `type T = _;`.
             let mut visitor = HirPlaceholderCollector::default();
@@ -698,6 +704,7 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) {
 
         hir::TraitItemKind::Type(_, None) => {
             tcx.ensure().item_bounds(def_id);
+            tcx.ensure().item_super_predicates(def_id);
             // #74612: Visit and try to find bad placeholders
             // even if there is no concrete type.
             let mut visitor = HirPlaceholderCollector::default();
@@ -1364,7 +1371,7 @@ fn infer_return_ty_for_fn_sig<'tcx>(
             // recursive function definition to leak out into the fn sig.
             let mut should_recover = false;
 
-            if let Some(ret_ty) = ret_ty.make_suggestable(tcx, false) {
+            if let Some(ret_ty) = ret_ty.make_suggestable(tcx, false, None) {
                 diag.span_suggestion(
                     ty.span,
                     "replace with the correct return type",
@@ -1442,7 +1449,7 @@ fn suggest_impl_trait<'tcx>(
             let ty::Tuple(types) = *args_tuple.kind() else {
                 return None;
             };
-            let types = types.make_suggestable(tcx, false)?;
+            let types = types.make_suggestable(tcx, false, None)?;
             let maybe_ret =
                 if item_ty.is_unit() { String::new() } else { format!(" -> {item_ty}") };
             Some(format!(
@@ -1500,7 +1507,7 @@ fn suggest_impl_trait<'tcx>(
         // FIXME(compiler-errors): We may benefit from resolving regions here.
         if ocx.select_where_possible().is_empty()
             && let item_ty = infcx.resolve_vars_if_possible(item_ty)
-            && let Some(item_ty) = item_ty.make_suggestable(tcx, false)
+            && let Some(item_ty) = item_ty.make_suggestable(tcx, false, None)
             && let Some(sugg) = formatter(
                 tcx,
                 infcx.resolve_vars_if_possible(args),
diff --git a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
index 78c390d0924..f914f1f9b17 100644
--- a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
+++ b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
@@ -1,5 +1,6 @@
 use super::ItemCtxt;
 use crate::astconv::{AstConv, PredicateFilter};
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
 use rustc_infer::traits::util;
 use rustc_middle::ty::GenericArgs;
@@ -19,6 +20,7 @@ fn associated_type_bounds<'tcx>(
     assoc_item_def_id: LocalDefId,
     ast_bounds: &'tcx [hir::GenericBound<'tcx>],
     span: Span,
+    filter: PredicateFilter,
 ) -> &'tcx [(ty::Clause<'tcx>, Span)] {
     let item_ty = Ty::new_projection(
         tcx,
@@ -27,7 +29,7 @@ fn associated_type_bounds<'tcx>(
     );
 
     let icx = ItemCtxt::new(tcx, assoc_item_def_id);
-    let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, PredicateFilter::All);
+    let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, filter);
     // Associated types are implicitly sized unless a `?Sized` bound is found
     icx.astconv().add_implicitly_sized(&mut bounds, item_ty, ast_bounds, None, span);
 
@@ -63,10 +65,11 @@ fn opaque_type_bounds<'tcx>(
     ast_bounds: &'tcx [hir::GenericBound<'tcx>],
     item_ty: Ty<'tcx>,
     span: Span,
+    filter: PredicateFilter,
 ) -> &'tcx [(ty::Clause<'tcx>, Span)] {
     ty::print::with_reduced_queries!({
         let icx = ItemCtxt::new(tcx, opaque_def_id);
-        let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, PredicateFilter::All);
+        let mut bounds = icx.astconv().compute_bounds(item_ty, ast_bounds, filter);
         // Opaque types are implicitly sized unless a `?Sized` bound is found
         icx.astconv().add_implicitly_sized(&mut bounds, item_ty, ast_bounds, None, span);
         debug!(?bounds);
@@ -79,6 +82,21 @@ pub(super) fn explicit_item_bounds(
     tcx: TyCtxt<'_>,
     def_id: LocalDefId,
 ) -> ty::EarlyBinder<&'_ [(ty::Clause<'_>, Span)]> {
+    explicit_item_bounds_with_filter(tcx, def_id, PredicateFilter::All)
+}
+
+pub(super) fn explicit_item_super_predicates(
+    tcx: TyCtxt<'_>,
+    def_id: LocalDefId,
+) -> ty::EarlyBinder<&'_ [(ty::Clause<'_>, Span)]> {
+    explicit_item_bounds_with_filter(tcx, def_id, PredicateFilter::SelfOnly)
+}
+
+pub(super) fn explicit_item_bounds_with_filter(
+    tcx: TyCtxt<'_>,
+    def_id: LocalDefId,
+    filter: PredicateFilter,
+) -> ty::EarlyBinder<&'_ [(ty::Clause<'_>, Span)]> {
     match tcx.opt_rpitit_info(def_id.to_def_id()) {
         // RPITIT's bounds are the same as opaque type bounds, but with
         // a projection self type.
@@ -95,6 +113,7 @@ pub(super) fn explicit_item_bounds(
                     ty::GenericArgs::identity_for_item(tcx, def_id),
                 ),
                 item.span,
+                filter,
             ));
         }
         Some(ty::ImplTraitInTraitData::Impl { .. }) => span_bug!(
@@ -109,7 +128,7 @@ pub(super) fn explicit_item_bounds(
             kind: hir::TraitItemKind::Type(bounds, _),
             span,
             ..
-        }) => associated_type_bounds(tcx, def_id, bounds, *span),
+        }) => associated_type_bounds(tcx, def_id, bounds, *span, filter),
         hir::Node::Item(hir::Item {
             kind: hir::ItemKind::OpaqueTy(hir::OpaqueTy { bounds, in_trait: false, .. }),
             span,
@@ -117,7 +136,7 @@ pub(super) fn explicit_item_bounds(
         }) => {
             let args = GenericArgs::identity_for_item(tcx, def_id);
             let item_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args);
-            opaque_type_bounds(tcx, def_id, bounds, item_ty, *span)
+            opaque_type_bounds(tcx, def_id, bounds, item_ty, *span, filter)
         }
         // Since RPITITs are astconv'd as projections in `ast_ty_to_ty`, when we're asking
         // for the item bounds of the *opaques* in a trait's default method signature, we
@@ -135,7 +154,7 @@ pub(super) fn explicit_item_bounds(
             let args = GenericArgs::identity_for_item(tcx, def_id);
             let item_ty = Ty::new_opaque(tcx, def_id.to_def_id(), args);
             tcx.arena.alloc_slice(
-                &opaque_type_bounds(tcx, def_id, bounds, item_ty, *span)
+                &opaque_type_bounds(tcx, def_id, bounds, item_ty, *span, filter)
                     .to_vec()
                     .fold_with(&mut AssocTyToOpaque { tcx, fn_def_id: fn_def_id.to_def_id() }),
             )
@@ -155,6 +174,31 @@ pub(super) fn item_bounds(
     })
 }
 
+pub(super) fn item_super_predicates(
+    tcx: TyCtxt<'_>,
+    def_id: DefId,
+) -> ty::EarlyBinder<&'_ ty::List<ty::Clause<'_>>> {
+    tcx.explicit_item_super_predicates(def_id).map_bound(|bounds| {
+        tcx.mk_clauses_from_iter(
+            util::elaborate(tcx, bounds.iter().map(|&(bound, _span)| bound)).filter_only_self(),
+        )
+    })
+}
+
+pub(super) fn item_non_self_assumptions(
+    tcx: TyCtxt<'_>,
+    def_id: DefId,
+) -> ty::EarlyBinder<&'_ ty::List<ty::Clause<'_>>> {
+    let all_bounds: FxIndexSet<_> = tcx.item_bounds(def_id).skip_binder().iter().collect();
+    let own_bounds: FxIndexSet<_> =
+        tcx.item_super_predicates(def_id).skip_binder().iter().collect();
+    if all_bounds.len() == own_bounds.len() {
+        ty::EarlyBinder::bind(ty::List::empty())
+    } else {
+        ty::EarlyBinder::bind(tcx.mk_clauses_from_iter(all_bounds.difference(&own_bounds).copied()))
+    }
+}
+
 struct AssocTyToOpaque<'tcx> {
     tcx: TyCtxt<'tcx>,
     fn_def_id: DefId,
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index fd86f2dd1b1..cec01abae4b 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -47,7 +47,7 @@ fn anon_const_type_of<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Ty<'tcx> {
             let ty = tcx.fold_regions(ty, |r, _| {
                 if r.is_erased() { ty::Region::new_error_misc(tcx) } else { r }
             });
-            let (ty, opt_sugg) = if let Some(ty) = ty.make_suggestable(tcx, false) {
+            let (ty, opt_sugg) = if let Some(ty) = ty.make_suggestable(tcx, false, None) {
                 (ty, Some((span, Applicability::MachineApplicable)))
             } else {
                 (ty, None)
@@ -587,7 +587,7 @@ fn infer_placeholder_type<'a>(
                     suggestions.clear();
                 }
 
-                if let Some(ty) = ty.make_suggestable(tcx, false) {
+                if let Some(ty) = ty.make_suggestable(tcx, false, None) {
                     err.span_suggestion(
                         span,
                         format!("provide a type for the {kind}"),
@@ -606,7 +606,7 @@ fn infer_placeholder_type<'a>(
             let mut diag = bad_placeholder(tcx, vec![span], kind);
 
             if !ty.references_error() {
-                if let Some(ty) = ty.make_suggestable(tcx, false) {
+                if let Some(ty) = ty.make_suggestable(tcx, false, None) {
                     diag.span_suggestion(
                         span,
                         "replace with the correct type",
diff --git a/compiler/rustc_hir_analysis/src/hir_wf_check.rs b/compiler/rustc_hir_analysis/src/hir_wf_check.rs
index 2a9101b3808..18848702fea 100644
--- a/compiler/rustc_hir_analysis/src/hir_wf_check.rs
+++ b/compiler/rustc_hir_analysis/src/hir_wf_check.rs
@@ -163,6 +163,16 @@ fn diagnostic_hir_wf_check<'tcx>(
                 kind: hir::GenericParamKind::Type { default: Some(ty), .. },
                 ..
             }) => vec![*ty],
+            hir::Node::AnonConst(_)
+                if let Some(const_param_id) =
+                    tcx.hir().opt_const_param_default_param_def_id(hir_id)
+                    && let hir::Node::GenericParam(hir::GenericParam {
+                        kind: hir::GenericParamKind::Const { ty, .. },
+                        ..
+                    }) = tcx.hir_node_by_def_id(const_param_id) =>
+            {
+                vec![*ty]
+            }
             ref node => bug!("Unexpected node {:?}", node),
         },
         WellFormedLoc::Param { function: _, param_idx } => {
diff --git a/compiler/rustc_hir_pretty/src/lib.rs b/compiler/rustc_hir_pretty/src/lib.rs
index 34c24583947..71fdcc76a70 100644
--- a/compiler/rustc_hir_pretty/src/lib.rs
+++ b/compiler/rustc_hir_pretty/src/lib.rs
@@ -1387,7 +1387,7 @@ impl<'a> State<'a> {
                 // Print `}`:
                 self.bclose_maybe_open(expr.span, true);
             }
-            hir::ExprKind::Let(&hir::Let { pat, ty, init, .. }) => {
+            hir::ExprKind::Let(&hir::LetExpr { pat, ty, init, .. }) => {
                 self.print_let(pat, ty, init);
             }
             hir::ExprKind::If(test, blk, elseopt) => {
@@ -1808,6 +1808,12 @@ impl<'a> State<'a> {
                     self.pclose();
                 }
             }
+            PatKind::Deref(inner) => {
+                self.word("deref!");
+                self.popen();
+                self.print_pat(inner);
+                self.pclose();
+            }
             PatKind::Ref(inner, mutbl) => {
                 let is_range_inner = matches!(inner.kind, PatKind::Range(..));
                 self.word("&");
diff --git a/compiler/rustc_hir_typeck/src/_match.rs b/compiler/rustc_hir_typeck/src/_match.rs
index 4b3359858f1..1805e9fbb98 100644
--- a/compiler/rustc_hir_typeck/src/_match.rs
+++ b/compiler/rustc_hir_typeck/src/_match.rs
@@ -317,7 +317,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         err.note("`if` expressions without `else` evaluate to `()`");
         err.help("consider adding an `else` block that evaluates to the expected type");
         *error = true;
-        if let ExprKind::Let(hir::Let { span, pat, init, .. }) = cond_expr.kind
+        if let ExprKind::Let(hir::LetExpr { span, pat, init, .. }) = cond_expr.kind
             && let ExprKind::Block(block, _) = then_expr.kind
             // Refutability checks occur on the MIR, so we approximate it here by checking
             // if we have an enum with a single variant or a struct in the pattern.
@@ -645,7 +645,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 for ty in [first_ty, second_ty] {
                     for (clause, _) in self
                         .tcx
-                        .explicit_item_bounds(rpit_def_id)
+                        .explicit_item_super_predicates(rpit_def_id)
                         .iter_instantiated_copied(self.tcx, args)
                     {
                         let pred = clause.kind().rebind(match clause.kind().skip_binder() {
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs
index 6e30cb02245..b32c5e2c357 100644
--- a/compiler/rustc_hir_typeck/src/closure.rs
+++ b/compiler/rustc_hir_typeck/src/closure.rs
@@ -329,7 +329,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     expected_ty,
                     closure_kind,
                     self.tcx
-                        .explicit_item_bounds(def_id)
+                        .explicit_item_super_predicates(def_id)
                         .iter_instantiated_copied(self.tcx, args)
                         .map(|(c, s)| (c.as_predicate(), s)),
                 ),
@@ -906,7 +906,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => self
                 .tcx
-                .explicit_item_bounds(def_id)
+                .explicit_item_super_predicates(def_id)
                 .iter_instantiated_copied(self.tcx, args)
                 .find_map(|(p, s)| get_future_output(p.as_predicate(), s))?,
             ty::Error(_) => return Some(ret_ty),
diff --git a/compiler/rustc_hir_typeck/src/expr.rs b/compiler/rustc_hir_typeck/src/expr.rs
index 1a142f27809..4c01c201ad2 100644
--- a/compiler/rustc_hir_typeck/src/expr.rs
+++ b/compiler/rustc_hir_typeck/src/expr.rs
@@ -1261,7 +1261,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
-    pub(super) fn check_expr_let(&self, let_expr: &'tcx hir::Let<'tcx>, hir_id: HirId) -> Ty<'tcx> {
+    pub(super) fn check_expr_let(
+        &self,
+        let_expr: &'tcx hir::LetExpr<'tcx>,
+        hir_id: HirId,
+    ) -> Ty<'tcx> {
         // for let statements, this is done in check_stmt
         let init = let_expr.init;
         self.warn_if_unreachable(init.hir_id, init.span, "block in `let` expression");
diff --git a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
index 43e95544594..f3d523efd68 100644
--- a/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
+++ b/compiler/rustc_hir_typeck/src/expr_use_visitor.rs
@@ -245,7 +245,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                 }
             }
 
-            hir::ExprKind::Let(hir::Let { pat, init, .. }) => {
+            hir::ExprKind::Let(hir::LetExpr { pat, init, .. }) => {
                 self.walk_local(init, pat, None, |t| t.borrow_expr(init, ty::ImmBorrow))
             }
 
@@ -463,6 +463,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                     }
                     PatKind::Or(_)
                     | PatKind::Box(_)
+                    | PatKind::Deref(_)
                     | PatKind::Ref(..)
                     | PatKind::Wild
                     | PatKind::Err(_) => {
diff --git a/compiler/rustc_hir_typeck/src/fallback.rs b/compiler/rustc_hir_typeck/src/fallback.rs
index c16e941d4c5..140618e97cc 100644
--- a/compiler/rustc_hir_typeck/src/fallback.rs
+++ b/compiler/rustc_hir_typeck/src/fallback.rs
@@ -4,12 +4,11 @@ use rustc_data_structures::{
     graph::{iterate::DepthFirstSearch, vec_graph::VecGraph},
     unord::{UnordBag, UnordMap, UnordSet},
 };
-use rustc_hir::def_id::CRATE_DEF_ID;
 use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
 use rustc_middle::ty::{self, Ty};
-use rustc_span::sym;
 
-enum DivergingFallbackBehavior {
+#[derive(Copy, Clone)]
+pub enum DivergingFallbackBehavior {
     /// Always fallback to `()` (aka "always spontaneous decay")
     FallbackToUnit,
     /// Sometimes fallback to `!`, but mainly fallback to `()` so that most of the crates are not broken.
@@ -78,9 +77,8 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
             return false;
         }
 
-        let diverging_behavior = self.diverging_fallback_behavior();
-        let diverging_fallback =
-            self.calculate_diverging_fallback(&unresolved_variables, diverging_behavior);
+        let diverging_fallback = self
+            .calculate_diverging_fallback(&unresolved_variables, self.diverging_fallback_behavior);
 
         // We do fallback in two passes, to try to generate
         // better error messages.
@@ -94,32 +92,6 @@ impl<'tcx> FnCtxt<'_, 'tcx> {
         fallback_occurred
     }
 
-    fn diverging_fallback_behavior(&self) -> DivergingFallbackBehavior {
-        let Some((mode, span)) = self
-            .tcx
-            .get_attr(CRATE_DEF_ID, sym::rustc_never_type_mode)
-            .map(|attr| (attr.value_str().unwrap(), attr.span))
-        else {
-            if self.tcx.features().never_type_fallback {
-                return DivergingFallbackBehavior::FallbackToNiko;
-            }
-
-            return DivergingFallbackBehavior::FallbackToUnit;
-        };
-
-        match mode {
-            sym::fallback_to_unit => DivergingFallbackBehavior::FallbackToUnit,
-            sym::fallback_to_niko => DivergingFallbackBehavior::FallbackToNiko,
-            sym::fallback_to_never => DivergingFallbackBehavior::FallbackToNever,
-            sym::no_fallback => DivergingFallbackBehavior::NoFallback,
-            _ => {
-                self.tcx.dcx().span_err(span, format!("unknown never type mode: `{mode}` (supported: `fallback_to_unit`, `fallback_to_niko`, `fallback_to_never` and `no_fallback`)"));
-
-                DivergingFallbackBehavior::FallbackToUnit
-            }
-        }
-    }
-
     fn fallback_effects(&self) -> bool {
         let unsolved_effects = self.unsolved_effects();
 
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index 5c56c6acd27..19f839b6240 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -45,6 +45,29 @@ use rustc_trait_selection::traits::{self, ObligationCauseCode, SelectionContext}
 use std::iter;
 use std::mem;
 
+#[derive(Clone, Copy, Default)]
+pub enum DivergingBlockBehavior {
+    /// This is the current stable behavior:
+    ///
+    /// ```rust
+    /// {
+    ///     return;
+    /// } // block has type = !, even though we are supposedly dropping it with `;`
+    /// ```
+    #[default]
+    Never,
+
+    /// Alternative behavior:
+    ///
+    /// ```ignore (very-unstable-new-attribute)
+    /// #![rustc_never_type_options(diverging_block_default = "unit")]
+    /// {
+    ///     return;
+    /// } // block has type = (), since we are dropping `!` from `return` with `;`
+    /// ```
+    Unit,
+}
+
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     pub(in super::super) fn check_casts(&mut self) {
         // don't hold the borrow to deferred_cast_checks while checking to avoid borrow checker errors
@@ -1710,7 +1733,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 //
                 // #41425 -- label the implicit `()` as being the
                 // "found type" here, rather than the "expected type".
-                if !self.diverges.get().is_always() {
+                if !self.diverges.get().is_always()
+                    || matches!(self.diverging_block_behavior, DivergingBlockBehavior::Unit)
+                {
                     // #50009 -- Do not point at the entire fn block span, point at the return type
                     // span, as it is the cause of the requirement, and
                     // `consider_hint_about_removing_semicolon` will point at the last expression
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
index 685b1af931e..1850463194d 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs
@@ -5,7 +5,10 @@ mod checks;
 mod suggestions;
 
 use crate::coercion::DynamicCoerceMany;
+use crate::fallback::DivergingFallbackBehavior;
+use crate::fn_ctxt::checks::DivergingBlockBehavior;
 use crate::{CoroutineTypes, Diverges, EnclosingBreakables, Inherited};
+use hir::def_id::CRATE_DEF_ID;
 use rustc_errors::{DiagCtxt, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -18,7 +21,7 @@ use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKin
 use rustc_middle::ty::{self, Const, Ty, TyCtxt, TypeVisitableExt};
 use rustc_session::Session;
 use rustc_span::symbol::Ident;
-use rustc_span::{self, Span, DUMMY_SP};
+use rustc_span::{self, sym, Span, DUMMY_SP};
 use rustc_trait_selection::traits::{ObligationCause, ObligationCauseCode, ObligationCtxt};
 
 use std::cell::{Cell, RefCell};
@@ -108,6 +111,9 @@ pub struct FnCtxt<'a, 'tcx> {
     pub(super) inh: &'a Inherited<'tcx>,
 
     pub(super) fallback_has_occurred: Cell<bool>,
+
+    pub(super) diverging_fallback_behavior: DivergingFallbackBehavior,
+    pub(super) diverging_block_behavior: DivergingBlockBehavior,
 }
 
 impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
@@ -116,6 +122,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         param_env: ty::ParamEnv<'tcx>,
         body_id: LocalDefId,
     ) -> FnCtxt<'a, 'tcx> {
+        let (diverging_fallback_behavior, diverging_block_behavior) =
+            parse_never_type_options_attr(inh.tcx);
         FnCtxt {
             body_id,
             param_env,
@@ -131,6 +139,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             }),
             inh,
             fallback_has_occurred: Cell::new(false),
+            diverging_fallback_behavior,
+            diverging_block_behavior,
         }
     }
 
@@ -374,3 +384,64 @@ impl<'tcx> LoweredTy<'tcx> {
         LoweredTy { raw, normalized }
     }
 }
+
+fn parse_never_type_options_attr(
+    tcx: TyCtxt<'_>,
+) -> (DivergingFallbackBehavior, DivergingBlockBehavior) {
+    use DivergingFallbackBehavior::*;
+
+    // Error handling is dubious here (unwraps), but that's probably fine for an internal attribute.
+    // Just don't write incorrect attributes <3
+
+    let mut fallback = None;
+    let mut block = None;
+
+    let items = tcx
+        .get_attr(CRATE_DEF_ID, sym::rustc_never_type_options)
+        .map(|attr| attr.meta_item_list().unwrap())
+        .unwrap_or_default();
+
+    for item in items {
+        if item.has_name(sym::fallback) && fallback.is_none() {
+            let mode = item.value_str().unwrap();
+            match mode {
+                sym::unit => fallback = Some(FallbackToUnit),
+                sym::niko => fallback = Some(FallbackToNiko),
+                sym::never => fallback = Some(FallbackToNever),
+                sym::no => fallback = Some(NoFallback),
+                _ => {
+                    tcx.dcx().span_err(item.span(), format!("unknown never type fallback mode: `{mode}` (supported: `unit`, `niko`, `never` and `no`)"));
+                }
+            };
+            continue;
+        }
+
+        if item.has_name(sym::diverging_block_default) && fallback.is_none() {
+            let mode = item.value_str().unwrap();
+            match mode {
+                sym::unit => block = Some(DivergingBlockBehavior::Unit),
+                sym::never => block = Some(DivergingBlockBehavior::Never),
+                _ => {
+                    tcx.dcx().span_err(item.span(), format!("unknown diverging block default: `{mode}` (supported: `unit` and `never`)"));
+                }
+            };
+            continue;
+        }
+
+        tcx.dcx().span_err(
+            item.span(),
+            format!(
+                "unknown never type option: `{}` (supported: `fallback`)",
+                item.name_or_empty()
+            ),
+        );
+    }
+
+    let fallback = fallback.unwrap_or_else(|| {
+        if tcx.features().never_type_fallback { FallbackToNiko } else { FallbackToUnit }
+    });
+
+    let block = block.unwrap_or_default();
+
+    (fallback, block)
+}
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
index 3f6f4cccba7..f4090feee17 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -809,7 +809,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return true;
             }
             &hir::FnRetTy::DefaultReturn(span) if expected.is_unit() => {
-                if let Some(found) = found.make_suggestable(self.tcx, false) {
+                if let Some(found) = found.make_suggestable(self.tcx, false, None) {
                     err.subdiagnostic(
                         self.dcx(),
                         errors::AddReturnTypeSuggestion::Add { span, found: found.to_string() },
diff --git a/compiler/rustc_hir_typeck/src/gather_locals.rs b/compiler/rustc_hir_typeck/src/gather_locals.rs
index 4d37f725c94..6dae1fab6dc 100644
--- a/compiler/rustc_hir_typeck/src/gather_locals.rs
+++ b/compiler/rustc_hir_typeck/src/gather_locals.rs
@@ -29,7 +29,7 @@ impl<'a> DeclOrigin<'a> {
     }
 }
 
-/// A declaration is an abstraction of [hir::Local] and [hir::Let].
+/// A declaration is an abstraction of [hir::Local] and [hir::LetExpr].
 ///
 /// It must have a hir_id, as this is how we connect gather_locals to the check functions.
 pub(super) struct Declaration<'a> {
@@ -48,9 +48,9 @@ impl<'a> From<&'a hir::Local<'a>> for Declaration<'a> {
     }
 }
 
-impl<'a> From<(&'a hir::Let<'a>, hir::HirId)> for Declaration<'a> {
-    fn from((let_expr, hir_id): (&'a hir::Let<'a>, hir::HirId)) -> Self {
-        let hir::Let { pat, ty, span, init, is_recovered: _ } = *let_expr;
+impl<'a> From<(&'a hir::LetExpr<'a>, hir::HirId)> for Declaration<'a> {
+    fn from((let_expr, hir_id): (&'a hir::LetExpr<'a>, hir::HirId)) -> Self {
+        let hir::LetExpr { pat, ty, span, init, is_recovered: _ } = *let_expr;
         Declaration { hir_id, pat, ty, span, init: Some(init), origin: DeclOrigin::LetExpr }
     }
 }
diff --git a/compiler/rustc_hir_typeck/src/mem_categorization.rs b/compiler/rustc_hir_typeck/src/mem_categorization.rs
index 9307cccf092..d949772f1a3 100644
--- a/compiler/rustc_hir_typeck/src/mem_categorization.rs
+++ b/compiler/rustc_hir_typeck/src/mem_categorization.rs
@@ -719,7 +719,7 @@ impl<'a, 'tcx> MemCategorizationContext<'a, 'tcx> {
                 self.cat_pattern_(place_with_id, subpat, op)?;
             }
 
-            PatKind::Box(subpat) | PatKind::Ref(subpat, _) => {
+            PatKind::Box(subpat) | PatKind::Ref(subpat, _) | PatKind::Deref(subpat) => {
                 // box p1, &p1, &mut p1. we can ignore the mutability of
                 // PatKind::Ref since that information is already contained
                 // in the type.
diff --git a/compiler/rustc_hir_typeck/src/op.rs b/compiler/rustc_hir_typeck/src/op.rs
index 79f574aa7fd..8969030d683 100644
--- a/compiler/rustc_hir_typeck/src/op.rs
+++ b/compiler/rustc_hir_typeck/src/op.rs
@@ -601,8 +601,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                             if let Some(output_def_id) = output_def_id
                                                 && let Some(trait_def_id) = trait_def_id
                                                 && self.tcx.parent(output_def_id) == trait_def_id
-                                                && let Some(output_ty) =
-                                                    output_ty.make_suggestable(self.tcx, false)
+                                                && let Some(output_ty) = output_ty
+                                                    .make_suggestable(self.tcx, false, None)
                                             {
                                                 Some(("Output", output_ty))
                                             } else {
diff --git a/compiler/rustc_hir_typeck/src/pat.rs b/compiler/rustc_hir_typeck/src/pat.rs
index 491da7eb2c2..dad43cb8abe 100644
--- a/compiler/rustc_hir_typeck/src/pat.rs
+++ b/compiler/rustc_hir_typeck/src/pat.rs
@@ -18,8 +18,7 @@ use rustc_span::edit_distance::find_best_match_for_name;
 use rustc_span::hygiene::DesugaringKind;
 use rustc_span::source_map::Spanned;
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::Span;
-use rustc_span::{BytePos, DUMMY_SP};
+use rustc_span::{BytePos, Span, DUMMY_SP};
 use rustc_target::abi::FieldIdx;
 use rustc_trait_selection::traits::{ObligationCause, Pattern};
 use ty::VariantDef;
@@ -212,6 +211,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.check_pat_tuple(pat.span, elements, ddpos, expected, pat_info)
             }
             PatKind::Box(inner) => self.check_pat_box(pat.span, inner, expected, pat_info),
+            PatKind::Deref(inner) => self.check_pat_deref(pat.span, inner, expected, pat_info),
             PatKind::Ref(inner, mutbl) => self.check_pat_ref(pat, inner, mutbl, expected, pat_info),
             PatKind::Slice(before, slice, after) => {
                 self.check_pat_slice(pat.span, before, slice, after, expected, pat_info)
@@ -295,6 +295,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             | PatKind::TupleStruct(..)
             | PatKind::Tuple(..)
             | PatKind::Box(_)
+            | PatKind::Deref(_)
             | PatKind::Range(..)
             | PatKind::Slice(..) => AdjustMode::Peel,
             // A never pattern behaves somewhat like a literal or unit variant.
@@ -760,6 +761,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         | PatKind::Binding(..)
                         | PatKind::Path(..)
                         | PatKind::Box(..)
+                        | PatKind::Deref(_)
                         | PatKind::Ref(..)
                         | PatKind::Lit(..)
                         | PatKind::Range(..)
@@ -1975,6 +1977,28 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         box_ty
     }
 
+    fn check_pat_deref(
+        &self,
+        span: Span,
+        inner: &'tcx Pat<'tcx>,
+        expected: Ty<'tcx>,
+        pat_info: PatInfo<'tcx, '_>,
+    ) -> Ty<'tcx> {
+        let tcx = self.tcx;
+        // FIXME(deref_patterns): use `DerefPure` for soundness
+        // FIXME(deref_patterns): use `DerefMut` when required
+        // <expected as Deref>::Target
+        let ty = Ty::new_projection(
+            tcx,
+            tcx.require_lang_item(hir::LangItem::DerefTarget, Some(span)),
+            [expected],
+        );
+        let ty = self.normalize(span, ty);
+        let ty = self.try_structurally_resolve_type(span, ty);
+        self.check_pat(inner, ty, pat_info);
+        expected
+    }
+
     // Precondition: Pat is Ref(inner)
     fn check_pat_ref(
         &self,
diff --git a/compiler/rustc_incremental/src/persist/dirty_clean.rs b/compiler/rustc_incremental/src/persist/dirty_clean.rs
index 24512dea939..5156a8d3479 100644
--- a/compiler/rustc_incremental/src/persist/dirty_clean.rs
+++ b/compiler/rustc_incremental/src/persist/dirty_clean.rs
@@ -148,7 +148,7 @@ pub fn check_dirty_clean_annotations(tcx: TyCtxt<'_>) {
 
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             dirty_clean_visitor.check_item(id.owner_id.def_id);
         }
 
diff --git a/compiler/rustc_index_macros/src/lib.rs b/compiler/rustc_index_macros/src/lib.rs
index 532cac5791e..015518ae4d6 100644
--- a/compiler/rustc_index_macros/src/lib.rs
+++ b/compiler/rustc_index_macros/src/lib.rs
@@ -34,13 +34,7 @@ mod newtype;
 #[proc_macro]
 #[cfg_attr(
     feature = "nightly",
-    allow_internal_unstable(
-        step_trait,
-        rustc_attrs,
-        trusted_step,
-        spec_option_partial_eq,
-        min_specialization
-    )
+    allow_internal_unstable(step_trait, rustc_attrs, trusted_step, min_specialization)
 )]
 pub fn newtype_index(input: TokenStream) -> TokenStream {
     newtype::newtype(input)
diff --git a/compiler/rustc_index_macros/src/newtype.rs b/compiler/rustc_index_macros/src/newtype.rs
index 0b25628b9e1..e5c2ba42483 100644
--- a/compiler/rustc_index_macros/src/newtype.rs
+++ b/compiler/rustc_index_macros/src/newtype.rs
@@ -156,32 +156,6 @@ impl Parse for Newtype {
             }
         };
 
-        let spec_partial_eq_impl = if let Lit::Int(max) = &max {
-            if let Ok(max_val) = max.base10_parse::<u32>() {
-                quote! {
-                    #gate_rustc_only
-                    impl core::option::SpecOptionPartialEq for #name {
-                        #[inline]
-                        fn eq(l: &Option<Self>, r: &Option<Self>) -> bool {
-                            if #max_val < u32::MAX {
-                                l.map(|i| i.as_u32()).unwrap_or(#max_val+1) == r.map(|i| i.as_u32()).unwrap_or(#max_val+1)
-                            } else {
-                                match (l, r) {
-                                    (Some(l), Some(r)) => r == l,
-                                    (None, None) => true,
-                                    _ => false
-                                }
-                            }
-                        }
-                    }
-                }
-            } else {
-                quote! {}
-            }
-        } else {
-            quote! {}
-        };
-
         Ok(Self(quote! {
             #(#attrs)*
             #[derive(Clone, Copy, PartialEq, Eq, Hash, #(#derive_paths),*)]
@@ -283,8 +257,6 @@ impl Parse for Newtype {
 
             #step
 
-            #spec_partial_eq_impl
-
             impl From<#name> for u32 {
                 #[inline]
                 fn from(v: #name) -> u32 {
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index 331b3b97c34..7ce6c35f8c3 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -403,8 +403,10 @@ impl<'tcx> InferCtxt<'tcx> {
         let future_trait = self.tcx.require_lang_item(LangItem::Future, None);
         let item_def_id = self.tcx.associated_item_def_ids(future_trait)[0];
 
-        self.tcx.explicit_item_bounds(def_id).iter_instantiated_copied(self.tcx, args).find_map(
-            |(predicate, _)| {
+        self.tcx
+            .explicit_item_super_predicates(def_id)
+            .iter_instantiated_copied(self.tcx, args)
+            .find_map(|(predicate, _)| {
                 predicate
                     .kind()
                     .map_bound(|kind| match kind {
@@ -417,8 +419,7 @@ impl<'tcx> InferCtxt<'tcx> {
                     })
                     .no_bound_vars()
                     .flatten()
-            },
-        )
+            })
     }
 }
 
diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index 0686994b037..ce9001ccb1c 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -546,40 +546,55 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                 }
             }
             InferSourceKind::FullyQualifiedMethodCall { receiver, successor, args, def_id } => {
-                let mut printer = fmt_printer(self, Namespace::ValueNS);
-                printer.print_def_path(def_id, args).unwrap();
-                let def_path = printer.into_buffer();
-
-                // We only care about whether we have to add `&` or `&mut ` for now.
-                // This is the case if the last adjustment is a borrow and the
-                // first adjustment was not a builtin deref.
-                let adjustment = match typeck_results.expr_adjustments(receiver) {
-                    [
-                        Adjustment { kind: Adjust::Deref(None), target: _ },
-                        ..,
-                        Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), target: _ },
-                    ] => "",
-                    [
-                        ..,
-                        Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(_, mut_)), target: _ },
-                    ] => hir::Mutability::from(*mut_).ref_prefix_str(),
-                    _ => "",
-                };
+                let placeholder = Some(self.next_ty_var(TypeVariableOrigin {
+                    span: rustc_span::DUMMY_SP,
+                    kind: TypeVariableOriginKind::MiscVariable,
+                }));
+                if let Some(args) = args.make_suggestable(self.infcx.tcx, true, placeholder) {
+                    let mut printer = fmt_printer(self, Namespace::ValueNS);
+                    printer.print_def_path(def_id, args).unwrap();
+                    let def_path = printer.into_buffer();
+
+                    // We only care about whether we have to add `&` or `&mut ` for now.
+                    // This is the case if the last adjustment is a borrow and the
+                    // first adjustment was not a builtin deref.
+                    let adjustment = match typeck_results.expr_adjustments(receiver) {
+                        [
+                            Adjustment { kind: Adjust::Deref(None), target: _ },
+                            ..,
+                            Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), target: _ },
+                        ] => "",
+                        [
+                            ..,
+                            Adjustment {
+                                kind: Adjust::Borrow(AutoBorrow::Ref(_, mut_)),
+                                target: _,
+                            },
+                        ] => hir::Mutability::from(*mut_).ref_prefix_str(),
+                        _ => "",
+                    };
 
-                multi_suggestions.push(SourceKindMultiSuggestion::new_fully_qualified(
-                    receiver.span,
-                    def_path,
-                    adjustment,
-                    successor,
-                ));
+                    multi_suggestions.push(SourceKindMultiSuggestion::new_fully_qualified(
+                        receiver.span,
+                        def_path,
+                        adjustment,
+                        successor,
+                    ));
+                }
             }
             InferSourceKind::ClosureReturn { ty, data, should_wrap_expr } => {
-                let ty_info = ty_to_string(self, ty, None);
-                multi_suggestions.push(SourceKindMultiSuggestion::new_closure_return(
-                    ty_info,
-                    data,
-                    should_wrap_expr,
-                ));
+                let placeholder = Some(self.next_ty_var(TypeVariableOrigin {
+                    span: rustc_span::DUMMY_SP,
+                    kind: TypeVariableOriginKind::MiscVariable,
+                }));
+                if let Some(ty) = ty.make_suggestable(self.infcx.tcx, true, placeholder) {
+                    let ty_info = ty_to_string(self, ty, None);
+                    multi_suggestions.push(SourceKindMultiSuggestion::new_closure_return(
+                        ty_info,
+                        data,
+                        should_wrap_expr,
+                    ));
+                }
             }
         }
         match error_code {
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
index 503645191aa..fe70b631cdb 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
@@ -13,8 +13,8 @@ use rustc_errors::{Applicability, Diag, ErrorGuaranteed, MultiSpan, Subdiagnosti
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{walk_ty, Visitor};
 use rustc_hir::{
-    self as hir, GenericBound, GenericParamKind, Item, ItemKind, Lifetime, LifetimeName, Node,
-    TyKind,
+    self as hir, GenericBound, GenericParam, GenericParamKind, Item, ItemKind, Lifetime,
+    LifetimeName, LifetimeParamKind, MissingLifetimeKind, Node, TyKind,
 };
 use rustc_middle::ty::{
     self, AssocItemContainer, StaticLifetimeVisitor, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor,
@@ -355,20 +355,8 @@ pub fn suggest_new_region_bound(
                     // introducing a new lifetime `'a` or making use of one from existing named lifetimes if any
                     if let Some(id) = scope_def_id
                         && let Some(generics) = tcx.hir().get_generics(id)
-                        && let mut spans_suggs = generics
-                            .params
-                            .iter()
-                            .filter(|p| p.is_elided_lifetime())
-                            .map(|p| {
-                                if p.span.hi() - p.span.lo() == rustc_span::BytePos(1) {
-                                    // Ampersand (elided without '_)
-                                    (p.span.shrink_to_hi(), format!("{name} "))
-                                } else {
-                                    // Underscore (elided with '_)
-                                    (p.span, name.to_string())
-                                }
-                            })
-                            .collect::<Vec<_>>()
+                        && let mut spans_suggs =
+                            make_elided_region_spans_suggs(name, generics.params.iter())
                         && spans_suggs.len() > 1
                     {
                         let use_lt = if existing_lt_name == None {
@@ -430,6 +418,57 @@ pub fn suggest_new_region_bound(
     }
 }
 
+fn make_elided_region_spans_suggs<'a>(
+    name: &str,
+    generic_params: impl Iterator<Item = &'a GenericParam<'a>>,
+) -> Vec<(Span, String)> {
+    let mut spans_suggs = Vec::new();
+    let mut bracket_span = None;
+    let mut consecutive_brackets = 0;
+
+    let mut process_consecutive_brackets =
+        |span: Option<Span>, spans_suggs: &mut Vec<(Span, String)>| {
+            if span
+                .is_some_and(|span| bracket_span.map_or(true, |bracket_span| span == bracket_span))
+            {
+                consecutive_brackets += 1;
+            } else if let Some(bracket_span) = bracket_span.take() {
+                let sugg = std::iter::once("<")
+                    .chain(std::iter::repeat(name).take(consecutive_brackets).intersperse(", "))
+                    .chain([">"])
+                    .collect();
+                spans_suggs.push((bracket_span.shrink_to_hi(), sugg));
+                consecutive_brackets = 0;
+            }
+            bracket_span = span;
+        };
+
+    for p in generic_params {
+        if let GenericParamKind::Lifetime { kind: LifetimeParamKind::Elided(kind) } = p.kind {
+            match kind {
+                MissingLifetimeKind::Underscore => {
+                    process_consecutive_brackets(None, &mut spans_suggs);
+                    spans_suggs.push((p.span, name.to_string()))
+                }
+                MissingLifetimeKind::Ampersand => {
+                    process_consecutive_brackets(None, &mut spans_suggs);
+                    spans_suggs.push((p.span.shrink_to_hi(), format!("{name} ")));
+                }
+                MissingLifetimeKind::Comma => {
+                    process_consecutive_brackets(None, &mut spans_suggs);
+                    spans_suggs.push((p.span.shrink_to_hi(), format!("{name}, ")));
+                }
+                MissingLifetimeKind::Brackets => {
+                    process_consecutive_brackets(Some(p.span), &mut spans_suggs);
+                }
+            }
+        }
+    }
+    process_consecutive_brackets(None, &mut spans_suggs);
+
+    spans_suggs
+}
+
 impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
     pub fn get_impl_ident_and_self_ty_from_trait(
         tcx: TyCtxt<'tcx>,
diff --git a/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs b/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs
index 24eaff08220..fda3564bdbe 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/note_and_explain.rs
@@ -299,8 +299,11 @@ impl<T> Trait<T> for X {
                     }
                     (ty::Dynamic(t, _, ty::DynKind::Dyn), ty::Alias(ty::Opaque, alias))
                         if let Some(def_id) = t.principal_def_id()
-                            && tcx.explicit_item_bounds(alias.def_id).skip_binder().iter().any(
-                                |(pred, _span)| match pred.kind().skip_binder() {
+                            && tcx
+                                .explicit_item_super_predicates(alias.def_id)
+                                .skip_binder()
+                                .iter()
+                                .any(|(pred, _span)| match pred.kind().skip_binder() {
                                     ty::ClauseKind::Trait(trait_predicate)
                                         if trait_predicate.polarity
                                             == ty::ImplPolarity::Positive =>
@@ -308,8 +311,7 @@ impl<T> Trait<T> for X {
                                         trait_predicate.def_id() == def_id
                                     }
                                     _ => false,
-                                },
-                            ) =>
+                                }) =>
                     {
                         diag.help(format!(
                             "you can box the `{}` to coerce it to `Box<{}>`, but you'll have to \
@@ -412,7 +414,7 @@ impl<T> Trait<T> for X {
                             ty::Alias(..) => values.expected,
                             _ => values.found,
                         };
-                        let preds = tcx.explicit_item_bounds(opaque_ty.def_id);
+                        let preds = tcx.explicit_item_super_predicates(opaque_ty.def_id);
                         for (pred, _span) in preds.skip_binder() {
                             let ty::ClauseKind::Trait(trait_predicate) = pred.kind().skip_binder()
                             else {
diff --git a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
index c39d0425f7e..5ae7f8bf504 100644
--- a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
+++ b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
@@ -13,6 +13,7 @@ use rustc_data_structures::graph::implementation::{
     Direction, Graph, NodeIndex, INCOMING, OUTGOING,
 };
 use rustc_data_structures::intern::Interned;
+use rustc_data_structures::unord::UnordSet;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::{self, Ty, TyCtxt};
@@ -139,8 +140,8 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         let mut var_data = self.construct_var_data();
 
         // Deduplicating constraints is shown to have a positive perf impact.
-        self.data.constraints.sort_by_key(|(constraint, _)| *constraint);
-        self.data.constraints.dedup_by_key(|(constraint, _)| *constraint);
+        let mut seen = UnordSet::default();
+        self.data.constraints.retain(|(constraint, _)| seen.insert(*constraint));
 
         if cfg!(debug_assertions) {
             self.dump_constraints();
@@ -888,12 +889,14 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                     }
 
                     Constraint::RegSubVar(region, _) | Constraint::VarSubReg(_, region) => {
-                        let constraint_idx =
-                            this.constraints.binary_search_by(|(c, _)| c.cmp(&edge.data)).unwrap();
-                        state.result.push(RegionAndOrigin {
-                            region,
-                            origin: this.constraints[constraint_idx].1.clone(),
-                        });
+                        let origin = this
+                            .constraints
+                            .iter()
+                            .find(|(c, _)| *c == edge.data)
+                            .unwrap()
+                            .1
+                            .clone();
+                        state.result.push(RegionAndOrigin { region, origin });
                     }
 
                     Constraint::RegSubReg(..) => panic!(
diff --git a/compiler/rustc_infer/src/infer/opaque_types/mod.rs b/compiler/rustc_infer/src/infer/opaque_types/mod.rs
index a6f8115c27e..02b8ded285f 100644
--- a/compiler/rustc_infer/src/infer/opaque_types/mod.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types/mod.rs
@@ -94,9 +94,6 @@ impl<'tcx> InferCtxt<'tcx> {
         cause: &ObligationCause<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> InferResult<'tcx, ()> {
-        if a.references_error() || b.references_error() {
-            return Ok(InferOk { value: (), obligations: vec![] });
-        }
         let process = |a: Ty<'tcx>, b: Ty<'tcx>| match *a.kind() {
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) if def_id.is_local() => {
                 let def_id = def_id.expect_local();
diff --git a/compiler/rustc_infer/src/infer/outlives/verify.rs b/compiler/rustc_infer/src/infer/outlives/verify.rs
index 3ef37bf3466..bd981c20567 100644
--- a/compiler/rustc_infer/src/infer/outlives/verify.rs
+++ b/compiler/rustc_infer/src/infer/outlives/verify.rs
@@ -300,7 +300,7 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         alias_ty: ty::AliasTy<'tcx>,
     ) -> impl Iterator<Item = ty::Region<'tcx>> {
         let tcx = self.tcx;
-        let bounds = tcx.item_bounds(alias_ty.def_id);
+        let bounds = tcx.item_super_predicates(alias_ty.def_id);
         trace!("{:#?}", bounds.skip_binder());
         bounds
             .iter_instantiated(tcx, alias_ty.args)
diff --git a/compiler/rustc_infer/src/infer/region_constraints/mod.rs b/compiler/rustc_infer/src/infer/region_constraints/mod.rs
index 0f3f2bc5fa6..3d6b54721d0 100644
--- a/compiler/rustc_infer/src/infer/region_constraints/mod.rs
+++ b/compiler/rustc_infer/src/infer/region_constraints/mod.rs
@@ -104,7 +104,7 @@ pub struct RegionConstraintData<'tcx> {
 }
 
 /// Represents a constraint that influences the inference process.
-#[derive(Clone, Copy, PartialEq, Eq, Debug, PartialOrd, Ord)]
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
 pub enum Constraint<'tcx> {
     /// A region variable is a subregion of another.
     VarSubVar(RegionVid, RegionVid),
diff --git a/compiler/rustc_infer/src/lib.rs b/compiler/rustc_infer/src/lib.rs
index 807d5500a90..ee9ce842d00 100644
--- a/compiler/rustc_infer/src/lib.rs
+++ b/compiler/rustc_infer/src/lib.rs
@@ -24,6 +24,7 @@
 #![feature(extend_one)]
 #![feature(let_chains)]
 #![feature(if_let_guard)]
+#![feature(iter_intersperse)]
 #![feature(iterator_try_collect)]
 #![feature(try_blocks)]
 #![feature(yeet_expr)]
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 1a82e6c6910..8ba14d37982 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -341,51 +341,22 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
 
             let sysroot = filesearch::materialize_sysroot(config.opts.maybe_sysroot.clone());
 
-            let (codegen_backend, target_override) = match config.make_codegen_backend {
-                None => {
-                    // Build a target without override, so that it can override the backend if needed
-                    let target =
-                        config::build_target_config(&early_dcx, &config.opts, None, &sysroot);
-
-                    let backend = util::get_codegen_backend(
-                        &early_dcx,
-                        &sysroot,
-                        config.opts.unstable_opts.codegen_backend.as_deref(),
-                        &target,
-                    );
-
-                    // target_override is documented to be called before init(), so this is okay
-                    let target_override = backend.target_override(&config.opts);
-
-                    // Assert that we don't use target's override of the backend and
-                    // backend's override of the target at the same time
-                    if config.opts.unstable_opts.codegen_backend.is_none()
-                        && target.default_codegen_backend.is_some()
-                        && target_override.is_some()
-                    {
-                        rustc_middle::bug!(
-                            "Codegen backend requested target override even though the target requested the backend"
-                        );
-                    }
-
-                    (backend, target_override)
-                }
+            let target = config::build_target_config(&early_dcx, &config.opts, &sysroot);
+
+            let codegen_backend = match config.make_codegen_backend {
+                None => util::get_codegen_backend(
+                    &early_dcx,
+                    &sysroot,
+                    config.opts.unstable_opts.codegen_backend.as_deref(),
+                    &target,
+                ),
                 Some(make_codegen_backend) => {
-                    // N.B. `make_codegen_backend` takes precedence over `target.default_codegen_backend`,
-                    //      which is ignored in this case.
-                    let backend = make_codegen_backend(&config.opts);
-
-                    // target_override is documented to be called before init(), so this is okay
-                    let target_override = backend.target_override(&config.opts);
-
-                    (backend, target_override)
+                    // N.B. `make_codegen_backend` takes precedence over
+                    // `target.default_codegen_backend`, which is ignored in this case.
+                    make_codegen_backend(&config.opts)
                 }
             };
 
-            // Re-build target with the (potential) override
-            let target_cfg =
-                config::build_target_config(&early_dcx, &config.opts, target_override, &sysroot);
-
             let temps_dir = config.opts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
 
             let bundle = match rustc_errors::fluent_bundle(
@@ -418,7 +389,7 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
                 locale_resources,
                 config.lint_caps,
                 config.file_loader,
-                target_cfg,
+                target,
                 sysroot,
                 util::rustc_version_str().unwrap_or("unknown"),
                 config.ice_file,
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 4d8e749d1da..8a27e9a6453 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -41,8 +41,7 @@ fn mk_session(matches: getopts::Matches) -> (Session, Cfg) {
 
     let sysroot = filesearch::materialize_sysroot(sessopts.maybe_sysroot.clone());
 
-    let target_cfg =
-        rustc_session::config::build_target_config(&early_dcx, &sessopts, None, &sysroot);
+    let target = rustc_session::config::build_target_config(&early_dcx, &sessopts, &sysroot);
 
     let sess = build_session(
         early_dcx,
@@ -53,7 +52,7 @@ fn mk_session(matches: getopts::Matches) -> (Session, Cfg) {
         vec![],
         Default::default(),
         None,
-        target_cfg,
+        target,
         sysroot,
         "",
         None,
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index 3e10879e241..0b757f95a99 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -295,7 +295,9 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
                 ty::Alias(ty::Opaque | ty::Projection, ty::AliasTy { def_id: def, .. }) => {
                     elaborate(
                         cx.tcx,
-                        cx.tcx.explicit_item_bounds(def).instantiate_identity_iter_copied(),
+                        cx.tcx
+                            .explicit_item_super_predicates(def)
+                            .instantiate_identity_iter_copied(),
                     )
                     // We only care about self bounds for the impl-trait
                     .filter_only_self()
@@ -863,7 +865,7 @@ trait UnusedDelimLint {
                 (iter, UnusedDelimsCtx::ForIterExpr, true, None, Some(body.span.lo()), true)
             }
 
-            Match(ref head, _) if Self::LINT_EXPR_IN_PATTERN_MATCHING_CTX => {
+            Match(ref head, ..) if Self::LINT_EXPR_IN_PATTERN_MATCHING_CTX => {
                 let left = e.span.lo() + rustc_span::BytePos(5);
                 (head, UnusedDelimsCtx::MatchScrutineeExpr, true, Some(left), None, true)
             }
@@ -1131,7 +1133,7 @@ impl EarlyLintPass for UnusedParens {
                 }
                 return;
             }
-            ExprKind::Match(ref _expr, ref arm) => {
+            ExprKind::Match(ref _expr, ref arm, _) => {
                 for a in arm {
                     if let Some(body) = &a.body {
                         self.check_unused_delims_expr(
@@ -1181,7 +1183,7 @@ impl EarlyLintPass for UnusedParens {
                 self.check_unused_parens_pat(cx, &f.pat, false, false, keep_space);
             },
             // Avoid linting on `i @ (p0 | .. | pn)` and `box (p0 | .. | pn)`, #64106.
-            Ident(.., Some(p)) | Box(p) => self.check_unused_parens_pat(cx, p, true, false, keep_space),
+            Ident(.., Some(p)) | Box(p) | Deref(p) => self.check_unused_parens_pat(cx, p, true, false, keep_space),
             // Avoid linting on `&(mut x)` as `&mut x` has a different meaning, #55342.
             // Also avoid linting on `& mut? (p0 | .. | pn)`, #64106.
             Ref(p, m) => self.check_unused_parens_pat(cx, p, true, *m == Mutability::Not, keep_space),
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 03783fa9798..596da58b091 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1063,6 +1063,20 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
         ty::EarlyBinder::bind(&*output)
     }
 
+    fn get_explicit_item_super_predicates(
+        self,
+        index: DefIndex,
+        tcx: TyCtxt<'tcx>,
+    ) -> ty::EarlyBinder<&'tcx [(ty::Clause<'tcx>, Span)]> {
+        let lazy = self.root.tables.explicit_item_super_predicates.get(self, index);
+        let output = if lazy.is_default() {
+            &mut []
+        } else {
+            tcx.arena.alloc_from_iter(lazy.decode((self, tcx)))
+        };
+        ty::EarlyBinder::bind(&*output)
+    }
+
     fn get_variant(
         self,
         kind: DefKind,
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 1c59af51589..1aabd296641 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -206,6 +206,7 @@ impl IntoArgs for (CrateNum, SimplifiedType) {
 
 provide! { tcx, def_id, other, cdata,
     explicit_item_bounds => { cdata.get_explicit_item_bounds(def_id.index, tcx) }
+    explicit_item_super_predicates => { cdata.get_explicit_item_super_predicates(def_id.index, tcx) }
     explicit_predicates_of => { table }
     generics_of => { table }
     inferred_outlives_of => { table_defaulted_array }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 1bd2c88ebaa..42724f7dd2b 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1491,6 +1491,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             }
             if let DefKind::OpaqueTy = def_kind {
                 self.encode_explicit_item_bounds(def_id);
+                self.encode_explicit_item_super_predicates(def_id);
                 self.tables
                     .is_type_alias_impl_trait
                     .set(def_id.index, self.tcx.is_type_alias_impl_trait(def_id));
@@ -1599,6 +1600,12 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
         record_defaulted_array!(self.tables.explicit_item_bounds[def_id] <- bounds);
     }
 
+    fn encode_explicit_item_super_predicates(&mut self, def_id: DefId) {
+        debug!("EncodeContext::encode_explicit_item_super_predicates({:?})", def_id);
+        let bounds = self.tcx.explicit_item_super_predicates(def_id).skip_binder();
+        record_defaulted_array!(self.tables.explicit_item_super_predicates[def_id] <- bounds);
+    }
+
     #[instrument(level = "debug", skip(self))]
     fn encode_info_for_assoc_item(&mut self, def_id: DefId) {
         let tcx = self.tcx;
@@ -1611,6 +1618,7 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             AssocItemContainer::TraitContainer => {
                 if let ty::AssocKind::Type = item.kind {
                     self.encode_explicit_item_bounds(def_id);
+                    self.encode_explicit_item_super_predicates(def_id);
                 }
             }
             AssocItemContainer::ImplContainer => {
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index 8aa31ef564f..5b0be8ac230 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -387,6 +387,7 @@ define_tables! {
     // corresponding DefPathHash.
     def_path_hashes: Table<DefIndex, u64>,
     explicit_item_bounds: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
+    explicit_item_super_predicates: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     inferred_outlives_of: Table<DefIndex, LazyArray<(ty::Clause<'static>, Span)>>,
     inherent_impls: Table<DefIndex, LazyArray<DefIndex>>,
     associated_types_for_impl_traits_in_associated_fn: Table<DefIndex, LazyArray<DefId>>,
diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index 5e74ce86007..a1bcee84d4c 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -166,12 +166,12 @@ impl<'hir> Map<'hir> {
 
     #[inline]
     pub fn items(self) -> impl Iterator<Item = ItemId> + 'hir {
-        self.tcx.hir_crate_items(()).items.iter().copied()
+        self.tcx.hir_crate_items(()).free_items.iter().copied()
     }
 
     #[inline]
     pub fn module_items(self, module: LocalModDefId) -> impl Iterator<Item = ItemId> + 'hir {
-        self.tcx.hir_module_items(module).items()
+        self.tcx.hir_module_items(module).free_items()
     }
 
     pub fn def_key(self, def_id: LocalDefId) -> DefKey {
@@ -418,7 +418,7 @@ impl<'hir> Map<'hir> {
         V: Visitor<'hir>,
     {
         let krate = self.tcx.hir_crate_items(());
-        walk_list!(visitor, visit_item, krate.items().map(|id| self.item(id)));
+        walk_list!(visitor, visit_item, krate.free_items().map(|id| self.item(id)));
         walk_list!(visitor, visit_trait_item, krate.trait_items().map(|id| self.trait_item(id)));
         walk_list!(visitor, visit_impl_item, krate.impl_items().map(|id| self.impl_item(id)));
         walk_list!(
@@ -436,7 +436,7 @@ impl<'hir> Map<'hir> {
         V: Visitor<'hir>,
     {
         let module = self.tcx.hir_module_items(module);
-        walk_list!(visitor, visit_item, module.items().map(|id| self.item(id)));
+        walk_list!(visitor, visit_item, module.free_items().map(|id| self.item(id)));
         walk_list!(visitor, visit_trait_item, module.trait_items().map(|id| self.trait_item(id)));
         walk_list!(visitor, visit_impl_item, module.impl_items().map(|id| self.impl_item(id)));
         walk_list!(
@@ -1197,7 +1197,7 @@ pub(super) fn hir_module_items(tcx: TyCtxt<'_>, module_id: LocalModDefId) -> Mod
     } = collector;
     return ModuleItems {
         submodules: submodules.into_boxed_slice(),
-        items: items.into_boxed_slice(),
+        free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
@@ -1226,7 +1226,7 @@ pub(crate) fn hir_crate_items(tcx: TyCtxt<'_>, _: ()) -> ModuleItems {
 
     return ModuleItems {
         submodules: submodules.into_boxed_slice(),
-        items: items.into_boxed_slice(),
+        free_items: items.into_boxed_slice(),
         trait_items: trait_items.into_boxed_slice(),
         impl_items: impl_items.into_boxed_slice(),
         foreign_items: foreign_items.into_boxed_slice(),
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
index f9fa8ac2f7a..28f7574f66f 100644
--- a/compiler/rustc_middle/src/hir/mod.rs
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -22,7 +22,7 @@ use rustc_span::{ErrorGuaranteed, ExpnId};
 #[derive(Debug, HashStable, Encodable, Decodable)]
 pub struct ModuleItems {
     submodules: Box<[OwnerId]>,
-    items: Box<[ItemId]>,
+    free_items: Box<[ItemId]>,
     trait_items: Box<[TraitItemId]>,
     impl_items: Box<[ImplItemId]>,
     foreign_items: Box<[ForeignItemId]>,
@@ -30,14 +30,22 @@ pub struct ModuleItems {
 }
 
 impl ModuleItems {
-    pub fn items(&self) -> impl Iterator<Item = ItemId> + '_ {
-        self.items.iter().copied()
+    /// Returns all non-associated locally defined items in all modules.
+    ///
+    /// Note that this does *not* include associated items of `impl` blocks! It also does not
+    /// include foreign items. If you want to e.g. get all functions, use `definitions()` below.
+    ///
+    /// However, this does include the `impl` blocks themselves.
+    pub fn free_items(&self) -> impl Iterator<Item = ItemId> + '_ {
+        self.free_items.iter().copied()
     }
 
     pub fn trait_items(&self) -> impl Iterator<Item = TraitItemId> + '_ {
         self.trait_items.iter().copied()
     }
 
+    /// Returns all items that are associated with some `impl` block (both inherent and trait impl
+    /// blocks).
     pub fn impl_items(&self) -> impl Iterator<Item = ImplItemId> + '_ {
         self.impl_items.iter().copied()
     }
@@ -47,7 +55,7 @@ impl ModuleItems {
     }
 
     pub fn owners(&self) -> impl Iterator<Item = OwnerId> + '_ {
-        self.items
+        self.free_items
             .iter()
             .map(|id| id.owner_id)
             .chain(self.trait_items.iter().map(|id| id.owner_id))
@@ -63,7 +71,7 @@ impl ModuleItems {
         &self,
         f: impl Fn(ItemId) -> Result<(), ErrorGuaranteed> + DynSend + DynSync,
     ) -> Result<(), ErrorGuaranteed> {
-        try_par_for_each_in(&self.items[..], |&id| f(id))
+        try_par_for_each_in(&self.free_items[..], |&id| f(id))
     }
 
     pub fn par_trait_items(
diff --git a/compiler/rustc_middle/src/macros.rs b/compiler/rustc_middle/src/macros.rs
index 0ee97a6bed0..f70ef51107f 100644
--- a/compiler/rustc_middle/src/macros.rs
+++ b/compiler/rustc_middle/src/macros.rs
@@ -11,12 +11,18 @@
 /// [`span_bug`]: crate::span_bug
 #[macro_export]
 macro_rules! bug {
-    () => ( $crate::bug!("impossible case reached") );
-    ($msg:expr) => ({ $crate::util::bug::bug_fmt(::std::format_args!($msg)) });
-    ($msg:expr,) => ({ $crate::bug!($msg) });
-    ($fmt:expr, $($arg:tt)+) => ({
+    () => (
+        $crate::bug!("impossible case reached")
+    );
+    ($msg:expr) => (
+        $crate::util::bug::bug_fmt(::std::format_args!($msg))
+    );
+    ($msg:expr,) => (
+        $crate::bug!($msg)
+    );
+    ($fmt:expr, $($arg:tt)+) => (
         $crate::util::bug::bug_fmt(::std::format_args!($fmt, $($arg)+))
-    });
+    );
 }
 
 /// A macro for triggering an ICE with a span.
@@ -30,11 +36,15 @@ macro_rules! bug {
 /// [`DiagCtxt::span_delayed_bug`]: rustc_errors::DiagCtxt::span_delayed_bug
 #[macro_export]
 macro_rules! span_bug {
-    ($span:expr, $msg:expr) => ({ $crate::util::bug::span_bug_fmt($span, ::std::format_args!($msg)) });
-    ($span:expr, $msg:expr,) => ({ $crate::span_bug!($span, $msg) });
-    ($span:expr, $fmt:expr, $($arg:tt)+) => ({
+    ($span:expr, $msg:expr) => (
+        $crate::util::bug::span_bug_fmt($span, ::std::format_args!($msg))
+    );
+    ($span:expr, $msg:expr,) => (
+        $crate::span_bug!($span, $msg)
+    );
+    ($span:expr, $fmt:expr, $($arg:tt)+) => (
         $crate::util::bug::span_bug_fmt($span, ::std::format_args!($fmt, $($arg)+))
-    });
+    );
 }
 
 ///////////////////////////////////////////////////////////////////////////
diff --git a/compiler/rustc_middle/src/mir/coverage.rs b/compiler/rustc_middle/src/mir/coverage.rs
index 645a417c322..588aa1f40d7 100644
--- a/compiler/rustc_middle/src/mir/coverage.rs
+++ b/compiler/rustc_middle/src/mir/coverage.rs
@@ -88,14 +88,13 @@ pub enum CoverageKind {
     /// Marks a span that might otherwise not be represented in MIR, so that
     /// coverage instrumentation can associate it with its enclosing block/BCB.
     ///
-    /// Only used by the `InstrumentCoverage` pass, and has no effect during
-    /// codegen.
+    /// Should be erased before codegen (at some point after `InstrumentCoverage`).
     SpanMarker,
 
     /// Marks its enclosing basic block with an ID that can be referred to by
     /// side data in [`BranchInfo`].
     ///
-    /// Has no effect during codegen.
+    /// Should be erased before codegen (at some point after `InstrumentCoverage`).
     BlockMarker { id: BlockMarkerId },
 
     /// Marks the point in MIR control flow represented by a coverage counter.
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
index 4047891d769..00faa211853 100644
--- a/compiler/rustc_middle/src/mir/interpret/allocation.rs
+++ b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -37,9 +37,16 @@ pub trait AllocBytes:
     /// Create a zeroed `AllocBytes` of the specified size and alignment.
     /// Returns `None` if we ran out of memory on the host.
     fn zeroed(size: Size, _align: Align) -> Option<Self>;
+
+    /// Gives direct access to the raw underlying storage.
+    ///
+    /// Crucially this pointer is compatible with:
+    /// - other pointers retunred by this method, and
+    /// - references returned from `deref()`, as long as there was no write.
+    fn as_mut_ptr(&mut self) -> *mut u8;
 }
 
-// Default `bytes` for `Allocation` is a `Box<[u8]>`.
+/// Default `bytes` for `Allocation` is a `Box<u8>`.
 impl AllocBytes for Box<[u8]> {
     fn from_bytes<'a>(slice: impl Into<Cow<'a, [u8]>>, _align: Align) -> Self {
         Box::<[u8]>::from(slice.into())
@@ -51,6 +58,11 @@ impl AllocBytes for Box<[u8]> {
         let bytes = unsafe { bytes.assume_init() };
         Some(bytes)
     }
+
+    fn as_mut_ptr(&mut self) -> *mut u8 {
+        // Carefully avoiding any intermediate references.
+        ptr::addr_of_mut!(**self).cast()
+    }
 }
 
 /// This type represents an Allocation in the Miri/CTFE core engine.
@@ -399,10 +411,6 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
 
 /// Byte accessors.
 impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes> {
-    pub fn base_addr(&self) -> *const u8 {
-        self.bytes.as_ptr()
-    }
-
     /// This is the entirely abstraction-violating way to just grab the raw bytes without
     /// caring about provenance or initialization.
     ///
@@ -452,13 +460,14 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
         Ok(self.get_bytes_unchecked(range))
     }
 
-    /// Just calling this already marks everything as defined and removes provenance,
-    /// so be sure to actually put data there!
+    /// This is the entirely abstraction-violating way to just get mutable access to the raw bytes.
+    /// Just calling this already marks everything as defined and removes provenance, so be sure to
+    /// actually overwrite all the data there!
     ///
     /// It is the caller's responsibility to check bounds and alignment beforehand.
     /// Most likely, you want to use the `PlaceTy` and `OperandTy`-based methods
     /// on `InterpCx` instead.
-    pub fn get_bytes_mut(
+    pub fn get_bytes_unchecked_for_overwrite(
         &mut self,
         cx: &impl HasDataLayout,
         range: AllocRange,
@@ -469,8 +478,9 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
         Ok(&mut self.bytes[range.start.bytes_usize()..range.end().bytes_usize()])
     }
 
-    /// A raw pointer variant of `get_bytes_mut` that avoids invalidating existing aliases into this memory.
-    pub fn get_bytes_mut_ptr(
+    /// A raw pointer variant of `get_bytes_unchecked_for_overwrite` that avoids invalidating existing immutable aliases
+    /// into this memory.
+    pub fn get_bytes_unchecked_for_overwrite_ptr(
         &mut self,
         cx: &impl HasDataLayout,
         range: AllocRange,
@@ -479,10 +489,19 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
         self.provenance.clear(range, cx)?;
 
         assert!(range.end().bytes_usize() <= self.bytes.len()); // need to do our own bounds-check
+        // Cruciall, we go via `AllocBytes::as_mut_ptr`, not `AllocBytes::deref_mut`.
         let begin_ptr = self.bytes.as_mut_ptr().wrapping_add(range.start.bytes_usize());
         let len = range.end().bytes_usize() - range.start.bytes_usize();
         Ok(ptr::slice_from_raw_parts_mut(begin_ptr, len))
     }
+
+    /// This gives direct mutable access to the entire buffer, just exposing their internal state
+    /// without reseting anything. Directly exposes `AllocBytes::as_mut_ptr`. Only works if
+    /// `OFFSET_IS_ADDR` is true.
+    pub fn get_bytes_unchecked_raw_mut(&mut self) -> *mut u8 {
+        assert!(Prov::OFFSET_IS_ADDR);
+        self.bytes.as_mut_ptr()
+    }
 }
 
 /// Reading and writing.
@@ -589,7 +608,8 @@ impl<Prov: Provenance, Extra, Bytes: AllocBytes> Allocation<Prov, Extra, Bytes>
         };
 
         let endian = cx.data_layout().endian;
-        let dst = self.get_bytes_mut(cx, range)?;
+        // Yes we do overwrite all the bytes in `dst`.
+        let dst = self.get_bytes_unchecked_for_overwrite(cx, range)?;
         write_target_uint(endian, dst, bytes).unwrap();
 
         // See if we have to also store some provenance.
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 984d4687ef8..48edbde68e5 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -20,6 +20,7 @@ use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
 use rustc_hir::{self, CoroutineDesugaring, CoroutineKind, ImplicitSelfKind};
 use rustc_hir::{self as hir, HirId};
 use rustc_session::Session;
+use rustc_span::source_map::Spanned;
 use rustc_target::abi::{FieldIdx, VariantIdx};
 
 use polonius_engine::Atom;
@@ -44,6 +45,7 @@ use std::ops::{Index, IndexMut};
 use std::{iter, mem};
 
 pub use self::query::*;
+use self::visit::TyContext;
 pub use basic_blocks::BasicBlocks;
 
 mod basic_blocks;
@@ -304,6 +306,21 @@ impl<'tcx> CoroutineInfo<'tcx> {
     }
 }
 
+/// Some item that needs to monomorphize successfully for a MIR body to be considered well-formed.
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash, HashStable, TyEncodable, TyDecodable)]
+#[derive(TypeFoldable, TypeVisitable)]
+pub enum MentionedItem<'tcx> {
+    /// A function that gets called. We don't necessarily know its precise type yet, since it can be
+    /// hidden behind a generic.
+    Fn(Ty<'tcx>),
+    /// A type that has its drop shim called.
+    Drop(Ty<'tcx>),
+    /// Unsizing casts might require vtables, so we have to record them.
+    UnsizeCast { source_ty: Ty<'tcx>, target_ty: Ty<'tcx> },
+    /// A closure that is coerced to a function pointer.
+    Closure(Ty<'tcx>),
+}
+
 /// The lowered representation of a single function.
 #[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable, TypeVisitable)]
 pub struct Body<'tcx> {
@@ -367,8 +384,24 @@ pub struct Body<'tcx> {
 
     /// Constants that are required to evaluate successfully for this MIR to be well-formed.
     /// We hold in this field all the constants we are not able to evaluate yet.
+    ///
+    /// This is soundness-critical, we make a guarantee that all consts syntactically mentioned in a
+    /// function have successfully evaluated if the function ever gets executed at runtime.
     pub required_consts: Vec<ConstOperand<'tcx>>,
 
+    /// Further items that were mentioned in this function and hence *may* become monomorphized,
+    /// depending on optimizations. We use this to avoid optimization-dependent compile errors: the
+    /// collector recursively traverses all "mentioned" items and evaluates all their
+    /// `required_consts`.
+    ///
+    /// This is *not* soundness-critical and the contents of this list are *not* a stable guarantee.
+    /// All that's relevant is that this set is optimization-level-independent, and that it includes
+    /// everything that the collector would consider "used". (For example, we currently compute this
+    /// set after drop elaboration, so some drop calls that can never be reached are not considered
+    /// "mentioned".) See the documentation of `CollectionMode` in
+    /// `compiler/rustc_monomorphize/src/collector.rs` for more context.
+    pub mentioned_items: Vec<Spanned<MentionedItem<'tcx>>>,
+
     /// Does this body use generic parameters. This is used for the `ConstEvaluatable` check.
     ///
     /// Note that this does not actually mean that this body is not computable right now.
@@ -445,6 +478,7 @@ impl<'tcx> Body<'tcx> {
             var_debug_info,
             span,
             required_consts: Vec::new(),
+            mentioned_items: Vec::new(),
             is_polymorphic: false,
             injection_phase: None,
             tainted_by_errors,
@@ -474,6 +508,7 @@ impl<'tcx> Body<'tcx> {
             spread_arg: None,
             span: DUMMY_SP,
             required_consts: Vec::new(),
+            mentioned_items: Vec::new(),
             var_debug_info: Vec::new(),
             is_polymorphic: false,
             injection_phase: None,
@@ -568,6 +603,17 @@ impl<'tcx> Body<'tcx> {
         }
     }
 
+    pub fn span_for_ty_context(&self, ty_context: TyContext) -> Span {
+        match ty_context {
+            TyContext::UserTy(span) => span,
+            TyContext::ReturnTy(source_info)
+            | TyContext::LocalDecl { source_info, .. }
+            | TyContext::YieldTy(source_info)
+            | TyContext::ResumeTy(source_info) => source_info.span,
+            TyContext::Location(loc) => self.source_info(loc).span,
+        }
+    }
+
     /// Returns the return type; it always return first element from `local_decls` array.
     #[inline]
     pub fn return_ty(&self) -> Ty<'tcx> {
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index 0ab797134c0..752f5845afb 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -124,6 +124,7 @@ pub enum AnalysisPhase {
     /// * [`TerminatorKind::FalseEdge`]
     /// * [`StatementKind::FakeRead`]
     /// * [`StatementKind::AscribeUserType`]
+    /// * [`StatementKind::Coverage`] with [`CoverageKind::BlockMarker`] or [`CoverageKind::SpanMarker`]
     /// * [`Rvalue::Ref`] with `BorrowKind::Fake`
     ///
     /// Furthermore, `Deref` projections must be the first projection within any place (if they
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 9f0d2a89e6d..10d92583a55 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -343,11 +343,14 @@ rustc_queries! {
         }
     }
 
-    /// Returns the list of bounds that can be used for
-    /// `SelectionCandidate::ProjectionCandidate(_)` and
-    /// `ProjectionTyCandidate::TraitDef`.
-    /// Specifically this is the bounds written on the trait's type
-    /// definition, or those after the `impl` keyword
+    /// Returns the list of bounds that are required to be satsified
+    /// by a implementation or definition. For associated types, these
+    /// must be satisfied for an implementation to be well-formed,
+    /// and for opaque types, these are required to be satisfied by
+    /// the hidden-type of the opaque.
+    ///
+    /// Syntactially, these are the bounds written on the trait's type
+    /// definition, or those after the `impl` keyword for an opaque:
     ///
     /// ```ignore (incomplete)
     /// type X: Bound + 'lt
@@ -363,7 +366,16 @@ rustc_queries! {
         desc { |tcx| "finding item bounds for `{}`", tcx.def_path_str(key) }
         cache_on_disk_if { key.is_local() }
         separate_provide_extern
-        feedable
+    }
+
+    /// The set of item bounds (see [`TyCtxt::explicit_item_bounds`]) that
+    /// share the `Self` type of the item. These are a subset of the bounds
+    /// that may explicitly be used for things like closure signature
+    /// deduction.
+    query explicit_item_super_predicates(key: DefId) -> ty::EarlyBinder<&'tcx [(ty::Clause<'tcx>, Span)]> {
+        desc { |tcx| "finding item bounds for `{}`", tcx.def_path_str(key) }
+        cache_on_disk_if { key.is_local() }
+        separate_provide_extern
     }
 
     /// Elaborated version of the predicates from `explicit_item_bounds`.
@@ -390,6 +402,14 @@ rustc_queries! {
         desc { |tcx| "elaborating item bounds for `{}`", tcx.def_path_str(key) }
     }
 
+    query item_super_predicates(key: DefId) -> ty::EarlyBinder<&'tcx ty::List<ty::Clause<'tcx>>> {
+        desc { |tcx| "elaborating item assumptions for `{}`", tcx.def_path_str(key) }
+    }
+
+    query item_non_self_assumptions(key: DefId) -> ty::EarlyBinder<&'tcx ty::List<ty::Clause<'tcx>>> {
+        desc { |tcx| "elaborating item assumptions for `{}`", tcx.def_path_str(key) }
+    }
+
     /// Look up all native libraries this crate depends on.
     /// These are assembled from the following places:
     /// - `extern` blocks (depending on their `link` attributes)
diff --git a/compiler/rustc_middle/src/thir.rs b/compiler/rustc_middle/src/thir.rs
index 96a61883cc1..f684f83a261 100644
--- a/compiler/rustc_middle/src/thir.rs
+++ b/compiler/rustc_middle/src/thir.rs
@@ -647,6 +647,7 @@ impl<'tcx> Pat<'tcx> {
             AscribeUserType { subpattern, .. }
             | Binding { subpattern: Some(subpattern), .. }
             | Deref { subpattern }
+            | DerefPattern { subpattern }
             | InlineConstant { subpattern, .. } => subpattern.walk_(it),
             Leaf { subpatterns } | Variant { subpatterns, .. } => {
                 subpatterns.iter().for_each(|field| field.pattern.walk_(it))
@@ -762,6 +763,11 @@ pub enum PatKind<'tcx> {
         subpattern: Box<Pat<'tcx>>,
     },
 
+    /// Deref pattern, written `box P` for now.
+    DerefPattern {
+        subpattern: Box<Pat<'tcx>>,
+    },
+
     /// One of the following:
     /// * `&str` (represented as a valtree), which will be handled as a string pattern and thus
     ///   exhaustiveness checking will detect if you use the same string twice in different
@@ -1172,6 +1178,9 @@ impl<'tcx> fmt::Display for Pat<'tcx> {
                 }
                 write!(f, "{subpattern}")
             }
+            PatKind::DerefPattern { ref subpattern } => {
+                write!(f, "deref!({subpattern})")
+            }
             PatKind::Constant { value } => write!(f, "{value}"),
             PatKind::InlineConstant { def: _, ref subpattern } => {
                 write!(f, "{} (from inline const)", subpattern)
diff --git a/compiler/rustc_middle/src/thir/visit.rs b/compiler/rustc_middle/src/thir/visit.rs
index 5952c296fb6..99ab006bcc0 100644
--- a/compiler/rustc_middle/src/thir/visit.rs
+++ b/compiler/rustc_middle/src/thir/visit.rs
@@ -229,6 +229,7 @@ pub fn walk_pat<'thir, 'tcx: 'thir, V: Visitor<'thir, 'tcx>>(
     match &pat.kind {
         AscribeUserType { subpattern, ascription: _ }
         | Deref { subpattern }
+        | DerefPattern { subpattern }
         | Binding {
             subpattern: Some(subpattern),
             mutability: _,
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 5de2e2fb1e7..8a87538e788 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1828,7 +1828,7 @@ impl<'tcx> TyCtxt<'tcx> {
         let ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) = ty.kind() else { return false };
         let future_trait = self.require_lang_item(LangItem::Future, None);
 
-        self.explicit_item_bounds(def_id).skip_binder().iter().any(|&(predicate, _)| {
+        self.explicit_item_super_predicates(def_id).skip_binder().iter().any(|&(predicate, _)| {
             let ty::ClauseKind::Trait(trait_predicate) = predicate.kind().skip_binder() else {
                 return false;
             };
diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs
index 05463b8554f..ee18647cdd8 100644
--- a/compiler/rustc_middle/src/ty/diagnostics.rs
+++ b/compiler/rustc_middle/src/ty/diagnostics.rs
@@ -91,7 +91,12 @@ pub trait IsSuggestable<'tcx>: Sized {
     /// inference variables to be suggestable.
     fn is_suggestable(self, tcx: TyCtxt<'tcx>, infer_suggestable: bool) -> bool;
 
-    fn make_suggestable(self, tcx: TyCtxt<'tcx>, infer_suggestable: bool) -> Option<Self>;
+    fn make_suggestable(
+        self,
+        tcx: TyCtxt<'tcx>,
+        infer_suggestable: bool,
+        placeholder: Option<Ty<'tcx>>,
+    ) -> Option<Self>;
 }
 
 impl<'tcx, T> IsSuggestable<'tcx> for T
@@ -103,8 +108,13 @@ where
         self.visit_with(&mut IsSuggestableVisitor { tcx, infer_suggestable }).is_continue()
     }
 
-    fn make_suggestable(self, tcx: TyCtxt<'tcx>, infer_suggestable: bool) -> Option<T> {
-        self.try_fold_with(&mut MakeSuggestableFolder { tcx, infer_suggestable }).ok()
+    fn make_suggestable(
+        self,
+        tcx: TyCtxt<'tcx>,
+        infer_suggestable: bool,
+        placeholder: Option<Ty<'tcx>>,
+    ) -> Option<T> {
+        self.try_fold_with(&mut MakeSuggestableFolder { tcx, infer_suggestable, placeholder }).ok()
     }
 }
 
@@ -559,6 +569,7 @@ impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for IsSuggestableVisitor<'tcx> {
 pub struct MakeSuggestableFolder<'tcx> {
     tcx: TyCtxt<'tcx>,
     infer_suggestable: bool,
+    placeholder: Option<Ty<'tcx>>,
 }
 
 impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for MakeSuggestableFolder<'tcx> {
@@ -572,19 +583,24 @@ impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for MakeSuggestableFolder<'tcx> {
         let t = match *t.kind() {
             Infer(InferTy::TyVar(_)) if self.infer_suggestable => t,
 
-            FnDef(def_id, args) => {
+            FnDef(def_id, args) if self.placeholder.is_none() => {
                 Ty::new_fn_ptr(self.tcx, self.tcx.fn_sig(def_id).instantiate(self.tcx, args))
             }
 
-            // FIXME(compiler-errors): We could replace these with infer, I guess.
             Closure(..)
+            | FnDef(..)
             | Infer(..)
             | Coroutine(..)
             | CoroutineWitness(..)
             | Bound(_, _)
             | Placeholder(_)
             | Error(_) => {
-                return Err(());
+                if let Some(placeholder) = self.placeholder {
+                    // We replace these with infer (which is passed in from an infcx).
+                    placeholder
+                } else {
+                    return Err(());
+                }
             }
 
             Alias(Opaque, AliasTy { def_id, .. }) => {
diff --git a/compiler/rustc_middle/src/ty/region.rs b/compiler/rustc_middle/src/ty/region.rs
index d21f0e6385c..c66b9864e46 100644
--- a/compiler/rustc_middle/src/ty/region.rs
+++ b/compiler/rustc_middle/src/ty/region.rs
@@ -251,6 +251,7 @@ impl<'tcx> Region<'tcx> {
             }
             ty::ReError(_) => {
                 flags = flags | TypeFlags::HAS_FREE_REGIONS;
+                flags = flags | TypeFlags::HAS_ERROR;
             }
         }
 
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
index a6526b06851..e1081423489 100644
--- a/compiler/rustc_middle/src/ty/util.rs
+++ b/compiler/rustc_middle/src/ty/util.rs
@@ -682,6 +682,9 @@ impl<'tcx> TyCtxt<'tcx> {
 
     /// Return the set of types that should be taken into account when checking
     /// trait bounds on a coroutine's internal state.
+    // FIXME(compiler-errors): We should remove this when the old solver goes away;
+    // and all other usages of this function should go through `bound_coroutine_hidden_types`
+    // instead.
     pub fn coroutine_hidden_types(
         self,
         def_id: DefId,
@@ -694,6 +697,33 @@ impl<'tcx> TyCtxt<'tcx> {
             .map(|decl| ty::EarlyBinder::bind(decl.ty))
     }
 
+    /// Return the set of types that should be taken into account when checking
+    /// trait bounds on a coroutine's internal state. This properly replaces
+    /// `ReErased` with new existential bound lifetimes.
+    pub fn bound_coroutine_hidden_types(
+        self,
+        def_id: DefId,
+    ) -> impl Iterator<Item = ty::EarlyBinder<ty::Binder<'tcx, Ty<'tcx>>>> {
+        let coroutine_layout = self.mir_coroutine_witnesses(def_id);
+        coroutine_layout
+            .as_ref()
+            .map_or_else(|| [].iter(), |l| l.field_tys.iter())
+            .filter(|decl| !decl.ignore_for_traits)
+            .map(move |decl| {
+                let mut vars = vec![];
+                let ty = self.fold_regions(decl.ty, |re, debruijn| {
+                    assert_eq!(re, self.lifetimes.re_erased);
+                    let var = ty::BoundVar::from_usize(vars.len());
+                    vars.push(ty::BoundVariableKind::Region(ty::BrAnon));
+                    ty::Region::new_bound(self, debruijn, ty::BoundRegion { var, kind: ty::BrAnon })
+                });
+                ty::EarlyBinder::bind(ty::Binder::bind_with_vars(
+                    ty,
+                    self.mk_bound_variable_kinds(&vars),
+                ))
+            })
+    }
+
     /// Expands the given impl trait type, stopping if the type is recursive.
     #[instrument(skip(self), level = "debug", ret)]
     pub fn try_expand_impl_trait_type(
@@ -998,8 +1028,10 @@ impl<'tcx> OpaqueTypeExpander<'tcx> {
                 Some(expanded_ty) => *expanded_ty,
                 None => {
                     if matches!(self.inspect_coroutine_fields, InspectCoroutineFields::Yes) {
-                        for bty in self.tcx.coroutine_hidden_types(def_id) {
-                            let hidden_ty = bty.instantiate(self.tcx, args);
+                        for bty in self.tcx.bound_coroutine_hidden_types(def_id) {
+                            let hidden_ty = self.tcx.instantiate_bound_regions_with_erased(
+                                bty.instantiate(self.tcx, args),
+                            );
                             self.fold_ty(hidden_ty);
                         }
                     }
diff --git a/compiler/rustc_mir_build/src/build/custom/mod.rs b/compiler/rustc_mir_build/src/build/custom/mod.rs
index 288b787798b..109ffedec55 100644
--- a/compiler/rustc_mir_build/src/build/custom/mod.rs
+++ b/compiler/rustc_mir_build/src/build/custom/mod.rs
@@ -56,6 +56,7 @@ pub(super) fn build_custom_mir<'tcx>(
         var_debug_info: Vec::new(),
         span,
         required_consts: Vec::new(),
+        mentioned_items: Vec::new(),
         is_polymorphic: false,
         tainted_by_errors: None,
         injection_phase: None,
diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index d2cbbf9be32..f4f452d474f 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -879,6 +879,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 self.visit_primary_bindings(subpattern, pattern_user_ty.deref(), f);
             }
 
+            PatKind::DerefPattern { ref subpattern } => {
+                self.visit_primary_bindings(subpattern, UserTypeProjections::none(), f);
+            }
+
             PatKind::AscribeUserType {
                 ref subpattern,
                 ascription: thir::Ascription { ref annotation, variance: _ },
diff --git a/compiler/rustc_mir_build/src/build/matches/util.rs b/compiler/rustc_mir_build/src/build/matches/util.rs
index d0d49c13f13..1148cd19a01 100644
--- a/compiler/rustc_mir_build/src/build/matches/util.rs
+++ b/compiler/rustc_mir_build/src/build/matches/util.rs
@@ -256,6 +256,12 @@ impl<'pat, 'tcx> MatchPair<'pat, 'tcx> {
                 subpairs.push(MatchPair::new(place_builder, subpattern, cx));
                 default_irrefutable()
             }
+
+            PatKind::DerefPattern { .. } => {
+                // FIXME(deref_patterns)
+                // Treat it like a wildcard for now.
+                default_irrefutable()
+            }
         };
 
         MatchPair { place, test_case, subpairs, pattern }
diff --git a/compiler/rustc_mir_build/src/check_unsafety.rs b/compiler/rustc_mir_build/src/check_unsafety.rs
index 1ce8da162bf..e04fe31a76f 100644
--- a/compiler/rustc_mir_build/src/check_unsafety.rs
+++ b/compiler/rustc_mir_build/src/check_unsafety.rs
@@ -250,6 +250,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                 | PatKind::Variant { .. }
                 | PatKind::Leaf { .. }
                 | PatKind::Deref { .. }
+                | PatKind::DerefPattern { .. }
                 | PatKind::Range { .. }
                 | PatKind::Slice { .. }
                 | PatKind::Array { .. } => {
@@ -310,7 +311,7 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                 }
                 visit::walk_pat(self, pat);
             }
-            PatKind::Deref { .. } => {
+            PatKind::Deref { .. } | PatKind::DerefPattern { .. } => {
                 let old_inside_adt = std::mem::replace(&mut self.inside_adt, false);
                 visit::walk_pat(self, pat);
                 self.inside_adt = old_inside_adt;
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index cfa853417ca..434ed16d5c6 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -481,6 +481,7 @@ impl<'p, 'tcx> MatchVisitor<'p, 'tcx> {
             // when the iterator is an uninhabited type. unreachable_code will trigger instead.
             hir::MatchSource::ForLoopDesugar if arms.len() == 1 => {}
             hir::MatchSource::ForLoopDesugar
+            | hir::MatchSource::Postfix
             | hir::MatchSource::Normal
             | hir::MatchSource::FormatArgs => report_arm_reachability(&cx, &report),
             // Unreachable patterns in try and await expressions occur when one of
diff --git a/compiler/rustc_mir_build/src/thir/pattern/mod.rs b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
index 03eda9a9322..0a7e9653377 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/mod.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/mod.rs
@@ -257,6 +257,9 @@ impl<'a, 'tcx> PatCtxt<'a, 'tcx> {
                 return self.lower_path(qpath, pat.hir_id, pat.span);
             }
 
+            hir::PatKind::Deref(subpattern) => {
+                PatKind::DerefPattern { subpattern: self.lower_pattern(subpattern) }
+            }
             hir::PatKind::Ref(subpattern, _) | hir::PatKind::Box(subpattern) => {
                 PatKind::Deref { subpattern: self.lower_pattern(subpattern) }
             }
diff --git a/compiler/rustc_mir_build/src/thir/print.rs b/compiler/rustc_mir_build/src/thir/print.rs
index d53704f89e7..16c4248a159 100644
--- a/compiler/rustc_mir_build/src/thir/print.rs
+++ b/compiler/rustc_mir_build/src/thir/print.rs
@@ -688,6 +688,12 @@ impl<'a, 'tcx> ThirPrinter<'a, 'tcx> {
                 self.print_pat(subpattern, depth_lvl + 2);
                 print_indented!(self, "}", depth_lvl + 1);
             }
+            PatKind::DerefPattern { subpattern } => {
+                print_indented!(self, "DerefPattern { ", depth_lvl + 1);
+                print_indented!(self, "subpattern:", depth_lvl + 2);
+                self.print_pat(subpattern, depth_lvl + 2);
+                print_indented!(self, "}", depth_lvl + 1);
+            }
             PatKind::Constant { value } => {
                 print_indented!(self, "Constant {", depth_lvl + 1);
                 print_indented!(self, format!("value: {:?}", value), depth_lvl + 2);
diff --git a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
index 5b4bc4fa134..aaf2035fc21 100644
--- a/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
+++ b/compiler/rustc_mir_transform/src/cleanup_post_borrowck.rs
@@ -5,15 +5,20 @@
 //!   - [`AscribeUserType`]
 //!   - [`FakeRead`]
 //!   - [`Assign`] statements with a [`Fake`] borrow
+//!   - [`Coverage`] statements of kind [`BlockMarker`] or [`SpanMarker`]
 //!
 //! [`AscribeUserType`]: rustc_middle::mir::StatementKind::AscribeUserType
 //! [`Assign`]: rustc_middle::mir::StatementKind::Assign
 //! [`FakeRead`]: rustc_middle::mir::StatementKind::FakeRead
 //! [`Nop`]: rustc_middle::mir::StatementKind::Nop
 //! [`Fake`]: rustc_middle::mir::BorrowKind::Fake
+//! [`Coverage`]: rustc_middle::mir::StatementKind::Coverage
+//! [`BlockMarker`]: rustc_middle::mir::coverage::CoverageKind::BlockMarker
+//! [`SpanMarker`]: rustc_middle::mir::coverage::CoverageKind::SpanMarker
 
 use crate::MirPass;
-use rustc_middle::mir::{Body, BorrowKind, Rvalue, StatementKind, TerminatorKind};
+use rustc_middle::mir::coverage::CoverageKind;
+use rustc_middle::mir::{Body, BorrowKind, Coverage, Rvalue, StatementKind, TerminatorKind};
 use rustc_middle::ty::TyCtxt;
 
 pub struct CleanupPostBorrowck;
@@ -25,6 +30,12 @@ impl<'tcx> MirPass<'tcx> for CleanupPostBorrowck {
                 match statement.kind {
                     StatementKind::AscribeUserType(..)
                     | StatementKind::Assign(box (_, Rvalue::Ref(_, BorrowKind::Fake, _)))
+                    | StatementKind::Coverage(box Coverage {
+                        // These kinds of coverage statements are markers inserted during
+                        // MIR building, and are not needed after InstrumentCoverage.
+                        kind: CoverageKind::BlockMarker { .. } | CoverageKind::SpanMarker { .. },
+                        ..
+                    })
                     | StatementKind::FakeRead(..) => statement.make_nop(),
                     _ => (),
                 }
diff --git a/compiler/rustc_mir_transform/src/coverage/counters.rs b/compiler/rustc_mir_transform/src/coverage/counters.rs
index 9a1d8bae6b4..69dc4f2ddea 100644
--- a/compiler/rustc_mir_transform/src/coverage/counters.rs
+++ b/compiler/rustc_mir_transform/src/coverage/counters.rs
@@ -1,13 +1,12 @@
+use std::fmt::{self, Debug};
+
 use rustc_data_structures::captures::Captures;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::graph::WithNumNodes;
-use rustc_index::bit_set::BitSet;
 use rustc_index::IndexVec;
-use rustc_middle::mir::coverage::*;
+use rustc_middle::mir::coverage::{CounterId, CovTerm, Expression, ExpressionId, Op};
 
-use super::graph::{BasicCoverageBlock, CoverageGraph, TraverseCoverageGraphWithLoops};
-
-use std::fmt::{self, Debug};
+use crate::coverage::graph::{BasicCoverageBlock, CoverageGraph, TraverseCoverageGraphWithLoops};
 
 /// The coverage counter or counter expression associated with a particular
 /// BCB node or BCB edge.
@@ -18,10 +17,6 @@ pub(super) enum BcbCounter {
 }
 
 impl BcbCounter {
-    fn is_expression(&self) -> bool {
-        matches!(self, Self::Expression { .. })
-    }
-
     pub(super) fn as_term(&self) -> CovTerm {
         match *self {
             BcbCounter::Counter { id, .. } => CovTerm::Counter(id),
@@ -60,10 +55,6 @@ pub(super) struct CoverageCounters {
     /// We currently don't iterate over this map, but if we do in the future,
     /// switch it back to `FxIndexMap` to avoid query stability hazards.
     bcb_edge_counters: FxHashMap<(BasicCoverageBlock, BasicCoverageBlock), BcbCounter>,
-    /// Tracks which BCBs have a counter associated with some incoming edge.
-    /// Only used by assertions, to verify that BCBs with incoming edge
-    /// counters do not have their own physical counters (expressions are allowed).
-    bcb_has_incoming_edge_counters: BitSet<BasicCoverageBlock>,
     /// Table of expression data, associating each expression ID with its
     /// corresponding operator (+ or -) and its LHS/RHS operands.
     expressions: IndexVec<ExpressionId, Expression>,
@@ -83,7 +74,6 @@ impl CoverageCounters {
             counter_increment_sites: IndexVec::new(),
             bcb_counters: IndexVec::from_elem_n(None, num_bcbs),
             bcb_edge_counters: FxHashMap::default(),
-            bcb_has_incoming_edge_counters: BitSet::new_empty(num_bcbs),
             expressions: IndexVec::new(),
         };
 
@@ -122,14 +112,6 @@ impl CoverageCounters {
     }
 
     fn set_bcb_counter(&mut self, bcb: BasicCoverageBlock, counter_kind: BcbCounter) -> BcbCounter {
-        assert!(
-            // If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
-            // have an expression (to be injected into an existing `BasicBlock` represented by this
-            // `BasicCoverageBlock`).
-            counter_kind.is_expression() || !self.bcb_has_incoming_edge_counters.contains(bcb),
-            "attempt to add a `Counter` to a BCB target with existing incoming edge counters"
-        );
-
         if let Some(replaced) = self.bcb_counters[bcb].replace(counter_kind) {
             bug!(
                 "attempt to set a BasicCoverageBlock coverage counter more than once; \
@@ -146,19 +128,6 @@ impl CoverageCounters {
         to_bcb: BasicCoverageBlock,
         counter_kind: BcbCounter,
     ) -> BcbCounter {
-        // If the BCB has an edge counter (to be injected into a new `BasicBlock`), it can also
-        // have an expression (to be injected into an existing `BasicBlock` represented by this
-        // `BasicCoverageBlock`).
-        if let Some(node_counter) = self.bcb_counter(to_bcb)
-            && !node_counter.is_expression()
-        {
-            bug!(
-                "attempt to add an incoming edge counter from {from_bcb:?} \
-                when the target BCB already has {node_counter:?}"
-            );
-        }
-
-        self.bcb_has_incoming_edge_counters.insert(to_bcb);
         if let Some(replaced) = self.bcb_edge_counters.insert((from_bcb, to_bcb), counter_kind) {
             bug!(
                 "attempt to set an edge counter more than once; from_bcb: \
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index f6a0945c222..4ec76eec3a9 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -565,7 +565,8 @@ impl<'tcx> Inliner<'tcx> {
         mut callee_body: Body<'tcx>,
     ) {
         let terminator = caller_body[callsite.block].terminator.take().unwrap();
-        let TerminatorKind::Call { args, destination, unwind, target, .. } = terminator.kind else {
+        let TerminatorKind::Call { func, args, destination, unwind, target, .. } = terminator.kind
+        else {
             bug!("unexpected terminator kind {:?}", terminator.kind);
         };
 
@@ -717,6 +718,24 @@ impl<'tcx> Inliner<'tcx> {
                 Const::Val(..) | Const::Unevaluated(..) => true,
             },
         ));
+        // Now that we incorporated the callee's `required_consts`, we can remove the callee from
+        // `mentioned_items` -- but we have to take their `mentioned_items` in return. This does
+        // some extra work here to save the monomorphization collector work later. It helps a lot,
+        // since monomorphization can avoid a lot of work when the "mentioned items" are similar to
+        // the actually used items. By doing this we can entirely avoid visiting the callee!
+        // We need to reconstruct the `required_item` for the callee so that we can find and
+        // remove it.
+        let callee_item = MentionedItem::Fn(func.ty(caller_body, self.tcx));
+        if let Some(idx) =
+            caller_body.mentioned_items.iter().position(|item| item.node == callee_item)
+        {
+            // We found the callee, so remove it and add its items instead.
+            caller_body.mentioned_items.remove(idx);
+            caller_body.mentioned_items.extend(callee_body.mentioned_items);
+        } else {
+            // If we can't find the callee, there's no point in adding its items.
+            // Probably it already got removed by being inlined elsewhere in the same function.
+        }
     }
 
     fn make_call_args(
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 5d89015d61c..24bc263e5a7 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -88,6 +88,7 @@ mod lint;
 mod lower_intrinsics;
 mod lower_slice_len;
 mod match_branches;
+mod mentioned_items;
 mod multiple_return_terminators;
 mod normalize_array_len;
 mod nrvo;
@@ -565,6 +566,10 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         tcx,
         body,
         &[
+            // Before doing anything, remember which items are being mentioned so that the set of items
+            // visited does not depend on the optimization level.
+            &mentioned_items::MentionedItems,
+            // Add some UB checks before any UB gets optimized away.
             &check_alignment::CheckAlignment,
             // Before inlining: trim down MIR with passes to reduce inlining work.
 
diff --git a/compiler/rustc_mir_transform/src/mentioned_items.rs b/compiler/rustc_mir_transform/src/mentioned_items.rs
new file mode 100644
index 00000000000..57b6126dece
--- /dev/null
+++ b/compiler/rustc_mir_transform/src/mentioned_items.rs
@@ -0,0 +1,117 @@
+use rustc_middle::mir::visit::Visitor;
+use rustc_middle::mir::{self, Location, MentionedItem, MirPass};
+use rustc_middle::ty::{self, adjustment::PointerCoercion, TyCtxt};
+use rustc_session::Session;
+use rustc_span::source_map::Spanned;
+
+pub struct MentionedItems;
+
+struct MentionedItemsVisitor<'a, 'tcx> {
+    tcx: TyCtxt<'tcx>,
+    body: &'a mir::Body<'tcx>,
+    mentioned_items: &'a mut Vec<Spanned<MentionedItem<'tcx>>>,
+}
+
+impl<'tcx> MirPass<'tcx> for MentionedItems {
+    fn is_enabled(&self, _sess: &Session) -> bool {
+        // If this pass is skipped the collector assume that nothing got mentioned! We could
+        // potentially skip it in opt-level 0 if we are sure that opt-level will never *remove* uses
+        // of anything, but that still seems fragile. Furthermore, even debug builds use level 1, so
+        // special-casing level 0 is just not worth it.
+        true
+    }
+
+    fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut mir::Body<'tcx>) {
+        debug_assert!(body.mentioned_items.is_empty());
+        let mut mentioned_items = Vec::new();
+        MentionedItemsVisitor { tcx, body, mentioned_items: &mut mentioned_items }.visit_body(body);
+        body.mentioned_items = mentioned_items;
+    }
+}
+
+// This visitor is carefully in sync with the one in `rustc_monomorphize::collector`. We are
+// visiting the exact same places but then instead of monomorphizing and creating `MonoItems`, we
+// have to remain generic and just recording the relevant information in `mentioned_items`, where it
+// will then be monomorphized later during "mentioned items" collection.
+impl<'tcx> Visitor<'tcx> for MentionedItemsVisitor<'_, 'tcx> {
+    fn visit_terminator(&mut self, terminator: &mir::Terminator<'tcx>, location: Location) {
+        self.super_terminator(terminator, location);
+        let span = || self.body.source_info(location).span;
+        match &terminator.kind {
+            mir::TerminatorKind::Call { func, .. } => {
+                let callee_ty = func.ty(self.body, self.tcx);
+                self.mentioned_items
+                    .push(Spanned { node: MentionedItem::Fn(callee_ty), span: span() });
+            }
+            mir::TerminatorKind::Drop { place, .. } => {
+                let ty = place.ty(self.body, self.tcx).ty;
+                self.mentioned_items.push(Spanned { node: MentionedItem::Drop(ty), span: span() });
+            }
+            mir::TerminatorKind::InlineAsm { ref operands, .. } => {
+                for op in operands {
+                    match *op {
+                        mir::InlineAsmOperand::SymFn { ref value } => {
+                            self.mentioned_items.push(Spanned {
+                                node: MentionedItem::Fn(value.const_.ty()),
+                                span: span(),
+                            });
+                        }
+                        _ => {}
+                    }
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn visit_rvalue(&mut self, rvalue: &mir::Rvalue<'tcx>, location: Location) {
+        self.super_rvalue(rvalue, location);
+        let span = || self.body.source_info(location).span;
+        match *rvalue {
+            // We need to detect unsizing casts that required vtables.
+            mir::Rvalue::Cast(
+                mir::CastKind::PointerCoercion(PointerCoercion::Unsize),
+                ref operand,
+                target_ty,
+            )
+            | mir::Rvalue::Cast(mir::CastKind::DynStar, ref operand, target_ty) => {
+                // This isn't monomorphized yet so we can't tell what the actual types are -- just
+                // add everything that may involve a vtable.
+                let source_ty = operand.ty(self.body, self.tcx);
+                let may_involve_vtable = match (
+                    source_ty.builtin_deref(true).map(|t| t.ty.kind()),
+                    target_ty.builtin_deref(true).map(|t| t.ty.kind()),
+                ) {
+                    (Some(ty::Array(..)), Some(ty::Str | ty::Slice(..))) => false, // &str/&[T] unsizing
+                    _ => true,
+                };
+                if may_involve_vtable {
+                    self.mentioned_items.push(Spanned {
+                        node: MentionedItem::UnsizeCast { source_ty, target_ty },
+                        span: span(),
+                    });
+                }
+            }
+            // Similarly, record closures that are turned into function pointers.
+            mir::Rvalue::Cast(
+                mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)),
+                ref operand,
+                _,
+            ) => {
+                let source_ty = operand.ty(self.body, self.tcx);
+                self.mentioned_items
+                    .push(Spanned { node: MentionedItem::Closure(source_ty), span: span() });
+            }
+            // And finally, function pointer reification casts.
+            mir::Rvalue::Cast(
+                mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer),
+                ref operand,
+                _,
+            ) => {
+                let fn_ty = operand.ty(self.body, self.tcx);
+                self.mentioned_items.push(Spanned { node: MentionedItem::Fn(fn_ty), span: span() });
+            }
+            _ => {}
+        }
+    }
+}
diff --git a/compiler/rustc_mir_transform/src/shim.rs b/compiler/rustc_mir_transform/src/shim.rs
index 28b502e8cab..71de64c6d26 100644
--- a/compiler/rustc_mir_transform/src/shim.rs
+++ b/compiler/rustc_mir_transform/src/shim.rs
@@ -17,7 +17,7 @@ use std::iter;
 
 use crate::{
     abort_unwinding_calls, add_call_guards, add_moves_for_packed_drops, deref_separator,
-    pass_manager as pm, remove_noop_landing_pads, simplify,
+    mentioned_items, pass_manager as pm, remove_noop_landing_pads, simplify,
 };
 use rustc_middle::mir::patch::MirPatch;
 use rustc_mir_dataflow::elaborate_drops::{self, DropElaborator, DropFlagMode, DropStyle};
@@ -112,6 +112,7 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> Body<'
                     tcx,
                     &mut body,
                     &[
+                        &mentioned_items::MentionedItems,
                         &abort_unwinding_calls::AbortUnwindingCalls,
                         &add_call_guards::CriticalCallEdges,
                     ],
@@ -143,6 +144,7 @@ fn make_shim<'tcx>(tcx: TyCtxt<'tcx>, instance: ty::InstanceDef<'tcx>) -> Body<'
         tcx,
         &mut result,
         &[
+            &mentioned_items::MentionedItems,
             &add_moves_for_packed_drops::AddMovesForPackedDrops,
             &deref_separator::Derefer,
             &remove_noop_landing_pads::RemoveNoopLandingPads,
diff --git a/compiler/rustc_monomorphize/src/collector.rs b/compiler/rustc_monomorphize/src/collector.rs
index abe691ba0d8..1a18a84b358 100644
--- a/compiler/rustc_monomorphize/src/collector.rs
+++ b/compiler/rustc_monomorphize/src/collector.rs
@@ -28,6 +28,7 @@
 //! - VTables
 //! - Object Shims
 //!
+//! The main entry point is `collect_crate_mono_items`, at the bottom of this file.
 //!
 //! General Algorithm
 //! -----------------
@@ -137,21 +138,61 @@
 //! just linked to and no node is created; which is exactly what we want, since
 //! no machine code should be generated in the current crate for such an item.
 //!
-//! Eager and Lazy Collection Mode
-//! ------------------------------
-//! Mono item collection can be performed in one of two modes:
+//! Eager and Lazy Collection Strategy
+//! ----------------------------------
+//! Mono item collection can be performed with one of two strategies:
 //!
-//! - Lazy mode means that items will only be instantiated when actually
+//! - Lazy strategy means that items will only be instantiated when actually
 //!   used. The goal is to produce the least amount of machine code
 //!   possible.
 //!
-//! - Eager mode is meant to be used in conjunction with incremental compilation
+//! - Eager strategy is meant to be used in conjunction with incremental compilation
 //!   where a stable set of mono items is more important than a minimal
-//!   one. Thus, eager mode will instantiate drop-glue for every drop-able type
+//!   one. Thus, eager strategy will instantiate drop-glue for every drop-able type
 //!   in the crate, even if no drop call for that type exists (yet). It will
 //!   also instantiate default implementations of trait methods, something that
 //!   otherwise is only done on demand.
 //!
+//! Collection-time const evaluation and "mentioned" items
+//! ------------------------------------------------------
+//!
+//! One important role of collection is to evaluate all constants that are used by all the items
+//! which are being collected. Codegen can then rely on only encountering constants that evaluate
+//! successfully, and if a constant fails to evaluate, the collector has much better context to be
+//! able to show where this constant comes up.
+//!
+//! However, the exact set of "used" items (collected as described above), and therefore the exact
+//! set of used constants, can depend on optimizations. Optimizing away dead code may optimize away
+//! a function call that uses a failing constant, so an unoptimized build may fail where an
+//! optimized build succeeds. This is undesirable.
+//!
+//! To avoid this, the collector has the concept of "mentioned" items. Some time during the MIR
+//! pipeline, before any optimization-level-dependent optimizations, we compute a list of all items
+//! that syntactically appear in the code. These are considered "mentioned", and even if they are in
+//! dead code and get optimized away (which makes them no longer "used"), they are still
+//! "mentioned". For every used item, the collector ensures that all mentioned items, recursively,
+//! do not use a failing constant. This is reflected via the [`CollectionMode`], which determines
+//! whether we are visiting a used item or merely a mentioned item.
+//!
+//! The collector and "mentioned items" gathering (which lives in `rustc_mir_transform::mentioned_items`)
+//! need to stay in sync in the following sense:
+//!
+//! - For every item that the collector gather that could eventually lead to build failure (most
+//!   likely due to containing a constant that fails to evaluate), a corresponding mentioned item
+//!   must be added. This should use the exact same strategy as the ecollector to make sure they are
+//!   in sync. However, while the collector works on monomorphized types, mentioned items are
+//!   collected on generic MIR -- so any time the collector checks for a particular type (such as
+//!   `ty::FnDef`), we have to just onconditionally add this as a mentioned item.
+//! - In `visit_mentioned_item`, we then do with that mentioned item exactly what the collector
+//!   would have done during regular MIR visiting. Basically you can think of the collector having
+//!   two stages, a pre-monomorphization stage and a post-monomorphization stage (usually quite
+//!   literally separated by a call to `self.monomorphize`); the pre-monomorphizationn stage is
+//!   duplicated in mentioned items gathering and the post-monomorphization stage is duplicated in
+//!   `visit_mentioned_item`.
+//! - Finally, as a performance optimization, the collector should fill `used_mentioned_item` during
+//!   its MIR traversal with exactly what mentioned item gathering would have added in the same
+//!   situation. This detects mentioned items that have *not* been optimized away and hence don't
+//!   need a dedicated traversal.
 //!
 //! Open Issues
 //! -----------
@@ -165,15 +206,16 @@
 //! regardless of whether it is actually needed or not.
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_data_structures::sync::{par_for_each_in, MTLock, MTLockRef};
+use rustc_data_structures::sync::{par_for_each_in, LRef, MTLock};
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId};
 use rustc_hir::lang_items::LangItem;
+use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{AllocId, ErrorHandled, GlobalAlloc, Scalar};
 use rustc_middle::mir::mono::{InstantiationMode, MonoItem};
 use rustc_middle::mir::visit::Visitor as MirVisitor;
-use rustc_middle::mir::{self, Location};
+use rustc_middle::mir::{self, Location, MentionedItem};
 use rustc_middle::query::TyCtxtAt;
 use rustc_middle::ty::adjustment::{CustomCoerceUnsized, PointerCoercion};
 use rustc_middle::ty::layout::ValidityRequirement;
@@ -183,7 +225,6 @@ use rustc_middle::ty::{
     TypeVisitableExt, VtblEntry,
 };
 use rustc_middle::ty::{GenericArgKind, GenericArgs};
-use rustc_middle::{middle::codegen_fn_attrs::CodegenFnAttrFlags, mir::visit::TyContext};
 use rustc_session::config::EntryFnType;
 use rustc_session::lint::builtin::LARGE_ASSIGNMENTS;
 use rustc_session::Limit;
@@ -199,7 +240,7 @@ use crate::errors::{
 };
 
 #[derive(PartialEq)]
-pub enum MonoItemCollectionMode {
+pub enum MonoItemCollectionStrategy {
     Eager,
     Lazy,
 }
@@ -214,6 +255,35 @@ pub struct UsageMap<'tcx> {
 
 type MonoItems<'tcx> = Vec<Spanned<MonoItem<'tcx>>>;
 
+/// The state that is shared across the concurrent threads that are doing collection.
+struct SharedState<'tcx> {
+    /// Items that have been or are currently being recursively collected.
+    visited: MTLock<FxHashSet<MonoItem<'tcx>>>,
+    /// Items that have been or are currently being recursively treated as "mentioned", i.e., their
+    /// consts are evaluated but nothing is added to the collection.
+    mentioned: MTLock<FxHashSet<MonoItem<'tcx>>>,
+    /// Which items are being used where, for better errors.
+    usage_map: MTLock<UsageMap<'tcx>>,
+}
+
+/// See module-level docs on some contect for "mentioned" items.
+#[derive(Copy, Clone, Debug, PartialEq)]
+enum CollectionMode {
+    /// Collect items that are used, i.e., actually needed for codegen.
+    ///
+    /// Which items are used can depend on optimization levels, as MIR optimizations can remove
+    /// uses.
+    UsedItems,
+    /// Collect items that are mentioned. The goal of this mode is that it is independent of
+    /// optimizations: the set of "mentioned" items is computed before optimizations are run.
+    ///
+    /// The exact contents of this set are *not* a stable guarantee. (For instance, it is currently
+    /// computed after drop-elaboration. If we ever do some optimizations even in debug builds, we
+    /// might decide to run them before computing mentioned items.) The key property of this set is
+    /// that it is optimization-independent.
+    MentionedItems,
+}
+
 impl<'tcx> UsageMap<'tcx> {
     fn new() -> UsageMap<'tcx> {
         UsageMap { used_map: FxHashMap::default(), user_map: FxHashMap::default() }
@@ -253,99 +323,40 @@ impl<'tcx> UsageMap<'tcx> {
     }
 }
 
-#[instrument(skip(tcx, mode), level = "debug")]
-pub fn collect_crate_mono_items(
-    tcx: TyCtxt<'_>,
-    mode: MonoItemCollectionMode,
-) -> (FxHashSet<MonoItem<'_>>, UsageMap<'_>) {
-    let _prof_timer = tcx.prof.generic_activity("monomorphization_collector");
-
-    let roots =
-        tcx.sess.time("monomorphization_collector_root_collections", || collect_roots(tcx, mode));
-
-    debug!("building mono item graph, beginning at roots");
-
-    let mut visited = MTLock::new(FxHashSet::default());
-    let mut usage_map = MTLock::new(UsageMap::new());
-    let recursion_limit = tcx.recursion_limit();
-
-    {
-        let visited: MTLockRef<'_, _> = &mut visited;
-        let usage_map: MTLockRef<'_, _> = &mut usage_map;
-
-        tcx.sess.time("monomorphization_collector_graph_walk", || {
-            par_for_each_in(roots, |root| {
-                let mut recursion_depths = DefIdMap::default();
-                collect_items_rec(
-                    tcx,
-                    dummy_spanned(root),
-                    visited,
-                    &mut recursion_depths,
-                    recursion_limit,
-                    usage_map,
-                );
-            });
-        });
-    }
-
-    (visited.into_inner(), usage_map.into_inner())
-}
-
-// Find all non-generic items by walking the HIR. These items serve as roots to
-// start monomorphizing from.
-#[instrument(skip(tcx, mode), level = "debug")]
-fn collect_roots(tcx: TyCtxt<'_>, mode: MonoItemCollectionMode) -> Vec<MonoItem<'_>> {
-    debug!("collecting roots");
-    let mut roots = Vec::new();
-
-    {
-        let entry_fn = tcx.entry_fn(());
-
-        debug!("collect_roots: entry_fn = {:?}", entry_fn);
-
-        let mut collector = RootCollector { tcx, mode, entry_fn, output: &mut roots };
-
-        let crate_items = tcx.hir_crate_items(());
-
-        for id in crate_items.items() {
-            collector.process_item(id);
-        }
-
-        for id in crate_items.impl_items() {
-            collector.process_impl_item(id);
-        }
-
-        collector.push_extra_entry_roots();
-    }
-
-    // We can only codegen items that are instantiable - items all of
-    // whose predicates hold. Luckily, items that aren't instantiable
-    // can't actually be used, so we can just skip codegenning them.
-    roots
-        .into_iter()
-        .filter_map(|Spanned { node: mono_item, .. }| {
-            mono_item.is_instantiable(tcx).then_some(mono_item)
-        })
-        .collect()
-}
-
 /// Collect all monomorphized items reachable from `starting_point`, and emit a note diagnostic if a
 /// post-monomorphization error is encountered during a collection step.
-#[instrument(skip(tcx, visited, recursion_depths, recursion_limit, usage_map), level = "debug")]
+///
+/// `mode` determined whether we are scanning for [used items][CollectionMode::UsedItems]
+/// or [mentioned items][CollectionMode::MentionedItems].
+#[instrument(skip(tcx, state, recursion_depths, recursion_limit), level = "debug")]
 fn collect_items_rec<'tcx>(
     tcx: TyCtxt<'tcx>,
     starting_item: Spanned<MonoItem<'tcx>>,
-    visited: MTLockRef<'_, FxHashSet<MonoItem<'tcx>>>,
+    state: LRef<'_, SharedState<'tcx>>,
     recursion_depths: &mut DefIdMap<usize>,
     recursion_limit: Limit,
-    usage_map: MTLockRef<'_, UsageMap<'tcx>>,
+    mode: CollectionMode,
 ) {
-    if !visited.lock_mut().insert(starting_item.node) {
-        // We've been here already, no need to search again.
-        return;
+    if mode == CollectionMode::UsedItems {
+        if !state.visited.lock_mut().insert(starting_item.node) {
+            // We've been here already, no need to search again.
+            return;
+        }
+    } else {
+        if state.visited.lock().contains(&starting_item.node) {
+            // We've already done a *full* visit on this one, no need to do the "mention" visit.
+            return;
+        }
+        if !state.mentioned.lock_mut().insert(starting_item.node) {
+            // We've been here already, no need to search again.
+            return;
+        }
+        // There's some risk that we first do a 'mention' visit and then a full visit. But there's no
+        // harm in that, the mention visit will trigger all the queries and the results are cached.
     }
 
-    let mut used_items = Vec::new();
+    let mut used_items = MonoItems::new();
+    let mut mentioned_items = MonoItems::new();
     let recursion_depth_reset;
 
     // Post-monomorphization errors MVP
@@ -373,37 +384,48 @@ fn collect_items_rec<'tcx>(
     // FIXME: don't rely on global state, instead bubble up errors. Note: this is very hard to do.
     let error_count = tcx.dcx().err_count();
 
+    // In `mentioned_items` we collect items that were mentioned in this MIR but possibly do not
+    // need to be monomorphized. This is done to ensure that optimizing away function calls does not
+    // hide const-eval errors that those calls would otherwise have triggered.
     match starting_item.node {
         MonoItem::Static(def_id) => {
-            let instance = Instance::mono(tcx, def_id);
+            recursion_depth_reset = None;
 
-            // Sanity check whether this ended up being collected accidentally
-            debug_assert!(should_codegen_locally(tcx, &instance));
+            // Statics always get evaluted (which is possible because they can't be generic), so for
+            // `MentionedItems` collection there's nothing to do here.
+            if mode == CollectionMode::UsedItems {
+                let instance = Instance::mono(tcx, def_id);
 
-            let DefKind::Static { nested, .. } = tcx.def_kind(def_id) else { bug!() };
-            // Nested statics have no type.
-            if !nested {
-                let ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
-                visit_drop_use(tcx, ty, true, starting_item.span, &mut used_items);
-            }
+                // Sanity check whether this ended up being collected accidentally
+                debug_assert!(should_codegen_locally(tcx, &instance));
 
-            recursion_depth_reset = None;
+                let DefKind::Static { nested, .. } = tcx.def_kind(def_id) else { bug!() };
+                // Nested statics have no type.
+                if !nested {
+                    let ty = instance.ty(tcx, ty::ParamEnv::reveal_all());
+                    visit_drop_use(tcx, ty, true, starting_item.span, &mut used_items);
+                }
+
+                if let Ok(alloc) = tcx.eval_static_initializer(def_id) {
+                    for &prov in alloc.inner().provenance().ptrs().values() {
+                        collect_alloc(tcx, prov.alloc_id(), &mut used_items);
+                    }
+                }
 
-            if let Ok(alloc) = tcx.eval_static_initializer(def_id) {
-                for &prov in alloc.inner().provenance().ptrs().values() {
-                    collect_alloc(tcx, prov.alloc_id(), &mut used_items);
+                if tcx.needs_thread_local_shim(def_id) {
+                    used_items.push(respan(
+                        starting_item.span,
+                        MonoItem::Fn(Instance {
+                            def: InstanceDef::ThreadLocalShim(def_id),
+                            args: GenericArgs::empty(),
+                        }),
+                    ));
                 }
             }
 
-            if tcx.needs_thread_local_shim(def_id) {
-                used_items.push(respan(
-                    starting_item.span,
-                    MonoItem::Fn(Instance {
-                        def: InstanceDef::ThreadLocalShim(def_id),
-                        args: GenericArgs::empty(),
-                    }),
-                ));
-            }
+            // mentioned_items stays empty since there's no codegen for statics. statics don't get
+            // optimized, and if they did then the const-eval interpreter would have to worry about
+            // mentioned_items.
         }
         MonoItem::Fn(instance) => {
             // Sanity check whether this ended up being collected accidentally
@@ -420,10 +442,20 @@ fn collect_items_rec<'tcx>(
             check_type_length_limit(tcx, instance);
 
             rustc_data_structures::stack::ensure_sufficient_stack(|| {
-                collect_used_items(tcx, instance, &mut used_items);
+                collect_items_of_instance(
+                    tcx,
+                    instance,
+                    &mut used_items,
+                    &mut mentioned_items,
+                    mode,
+                )
             });
         }
         MonoItem::GlobalAsm(item_id) => {
+            assert!(
+                mode == CollectionMode::UsedItems,
+                "should never encounter global_asm when collecting mentioned items"
+            );
             recursion_depth_reset = None;
 
             let item = tcx.hir().item(item_id);
@@ -459,8 +491,10 @@ fn collect_items_rec<'tcx>(
             } else {
                 span_bug!(item.span, "Mismatch between hir::Item type and MonoItem type")
             }
+
+            // mention_items stays empty as nothing gets optimized here.
         }
-    }
+    };
 
     // Check for PMEs and emit a diagnostic if one happened. To try to show relevant edges of the
     // mono item graph.
@@ -474,10 +508,41 @@ fn collect_items_rec<'tcx>(
             formatted_item,
         });
     }
-    usage_map.lock_mut().record_used(starting_item.node, &used_items);
+    // Only updating `usage_map` for used items as otherwise we may be inserting the same item
+    // multiple times (if it is first 'mentioned' and then later actuall used), and the usage map
+    // logic does not like that.
+    // This is part of the output of collection and hence only relevant for "used" items.
+    // ("Mentioned" items are only considered internally during collection.)
+    if mode == CollectionMode::UsedItems {
+        state.usage_map.lock_mut().record_used(starting_item.node, &used_items);
+    }
 
-    for used_item in used_items {
-        collect_items_rec(tcx, used_item, visited, recursion_depths, recursion_limit, usage_map);
+    if mode == CollectionMode::MentionedItems {
+        assert!(used_items.is_empty(), "'mentioned' collection should never encounter used items");
+    } else {
+        for used_item in used_items {
+            collect_items_rec(
+                tcx,
+                used_item,
+                state,
+                recursion_depths,
+                recursion_limit,
+                CollectionMode::UsedItems,
+            );
+        }
+    }
+
+    // Walk over mentioned items *after* used items, so that if an item is both mentioned and used then
+    // the loop above has fully collected it, so this loop will skip it.
+    for mentioned_item in mentioned_items {
+        collect_items_rec(
+            tcx,
+            mentioned_item,
+            state,
+            recursion_depths,
+            recursion_limit,
+            CollectionMode::MentionedItems,
+        );
     }
 
     if let Some((def_id, depth)) = recursion_depth_reset {
@@ -596,7 +661,10 @@ fn check_type_length_limit<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) {
 struct MirUsedCollector<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     body: &'a mir::Body<'tcx>,
-    output: &'a mut MonoItems<'tcx>,
+    used_items: &'a mut MonoItems<'tcx>,
+    /// See the comment in `collect_items_of_instance` for the purpose of this set.
+    /// Note that this contains *not-monomorphized* items!
+    used_mentioned_items: &'a mut FxHashSet<MentionedItem<'tcx>>,
     instance: Instance<'tcx>,
     /// Spans for move size lints already emitted. Helps avoid duplicate lints.
     move_size_spans: Vec<Span>,
@@ -606,11 +674,11 @@ struct MirUsedCollector<'a, 'tcx> {
 }
 
 impl<'a, 'tcx> MirUsedCollector<'a, 'tcx> {
-    pub fn monomorphize<T>(&self, value: T) -> T
+    fn monomorphize<T>(&self, value: T) -> T
     where
         T: TypeFoldable<TyCtxt<'tcx>>,
     {
-        debug!("monomorphize: self.instance={:?}", self.instance);
+        trace!("monomorphize: self.instance={:?}", self.instance);
         self.instance.instantiate_mir_and_normalize_erasing_regions(
             self.tcx,
             ty::ParamEnv::reveal_all(),
@@ -735,6 +803,31 @@ impl<'a, 'tcx> MirUsedCollector<'a, 'tcx> {
         );
         self.move_size_spans.push(span);
     }
+
+    /// Evaluates a *not yet monomorphized* constant.
+    fn eval_constant(
+        &mut self,
+        constant: &mir::ConstOperand<'tcx>,
+    ) -> Option<mir::ConstValue<'tcx>> {
+        let const_ = self.monomorphize(constant.const_);
+        let param_env = ty::ParamEnv::reveal_all();
+        // Evaluate the constant. This makes const eval failure a collection-time error (rather than
+        // a codegen-time error). rustc stops after collection if there was an error, so this
+        // ensures codegen never has to worry about failing consts.
+        // (codegen relies on this and ICEs will happen if this is violated.)
+        match const_.eval(self.tcx, param_env, constant.span) {
+            Ok(v) => Some(v),
+            Err(ErrorHandled::TooGeneric(..)) => span_bug!(
+                constant.span,
+                "collection encountered polymorphic constant: {:?}",
+                const_
+            ),
+            Err(err @ ErrorHandled::Reported(..)) => {
+                err.emit_note(self.tcx);
+                return None;
+            }
+        }
+    }
 }
 
 impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
@@ -753,8 +846,11 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 target_ty,
             )
             | mir::Rvalue::Cast(mir::CastKind::DynStar, ref operand, target_ty) => {
-                let target_ty = self.monomorphize(target_ty);
                 let source_ty = operand.ty(self.body, self.tcx);
+                // *Before* monomorphizing, record that we already handled this mention.
+                self.used_mentioned_items
+                    .insert(MentionedItem::UnsizeCast { source_ty, target_ty });
+                let target_ty = self.monomorphize(target_ty);
                 let source_ty = self.monomorphize(source_ty);
                 let (source_ty, target_ty) =
                     find_vtable_types_for_unsizing(self.tcx.at(span), source_ty, target_ty);
@@ -769,7 +865,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                         target_ty,
                         source_ty,
                         span,
-                        self.output,
+                        self.used_items,
                     );
                 }
             }
@@ -779,8 +875,10 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 _,
             ) => {
                 let fn_ty = operand.ty(self.body, self.tcx);
+                // *Before* monomorphizing, record that we already handled this mention.
+                self.used_mentioned_items.insert(MentionedItem::Fn(fn_ty));
                 let fn_ty = self.monomorphize(fn_ty);
-                visit_fn_use(self.tcx, fn_ty, false, span, self.output);
+                visit_fn_use(self.tcx, fn_ty, false, span, self.used_items);
             }
             mir::Rvalue::Cast(
                 mir::CastKind::PointerCoercion(PointerCoercion::ClosureFnPointer(_)),
@@ -788,20 +886,17 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 _,
             ) => {
                 let source_ty = operand.ty(self.body, self.tcx);
+                // *Before* monomorphizing, record that we already handled this mention.
+                self.used_mentioned_items.insert(MentionedItem::Closure(source_ty));
                 let source_ty = self.monomorphize(source_ty);
-                match *source_ty.kind() {
-                    ty::Closure(def_id, args) => {
-                        let instance = Instance::resolve_closure(
-                            self.tcx,
-                            def_id,
-                            args,
-                            ty::ClosureKind::FnOnce,
-                        );
-                        if should_codegen_locally(self.tcx, &instance) {
-                            self.output.push(create_fn_mono_item(self.tcx, instance, span));
-                        }
+                if let ty::Closure(def_id, args) = *source_ty.kind() {
+                    let instance =
+                        Instance::resolve_closure(self.tcx, def_id, args, ty::ClosureKind::FnOnce);
+                    if should_codegen_locally(self.tcx, &instance) {
+                        self.used_items.push(create_fn_mono_item(self.tcx, instance, span));
                     }
-                    _ => bug!(),
+                } else {
+                    bug!()
                 }
             }
             mir::Rvalue::ThreadLocalRef(def_id) => {
@@ -809,7 +904,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
                 let instance = Instance::mono(self.tcx, def_id);
                 if should_codegen_locally(self.tcx, &instance) {
                     trace!("collecting thread-local static {:?}", def_id);
-                    self.output.push(respan(span, MonoItem::Static(def_id)));
+                    self.used_items.push(respan(span, MonoItem::Static(def_id)));
                 }
             }
             _ => { /* not interesting */ }
@@ -822,26 +917,9 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
     /// to ensure that the constant evaluates successfully and walk the result.
     #[instrument(skip(self), level = "debug")]
     fn visit_constant(&mut self, constant: &mir::ConstOperand<'tcx>, location: Location) {
-        let const_ = self.monomorphize(constant.const_);
-        let param_env = ty::ParamEnv::reveal_all();
-        // Evaluate the constant. This makes const eval failure a collection-time error (rather than
-        // a codegen-time error). rustc stops after collection if there was an error, so this
-        // ensures codegen never has to worry about failing consts.
-        // (codegen relies on this and ICEs will happen if this is violated.)
-        let val = match const_.eval(self.tcx, param_env, constant.span) {
-            Ok(v) => v,
-            Err(ErrorHandled::TooGeneric(..)) => span_bug!(
-                self.body.source_info(location).span,
-                "collection encountered polymorphic constant: {:?}",
-                const_
-            ),
-            Err(err @ ErrorHandled::Reported(..)) => {
-                err.emit_note(self.tcx);
-                return;
-            }
-        };
-        collect_const_value(self.tcx, val, self.output);
-        MirVisitor::visit_ty(self, const_.ty(), TyContext::Location(location));
+        // No `super_constant` as we don't care about `visit_ty`/`visit_ty_const`.
+        let Some(val) = self.eval_constant(constant) else { return };
+        collect_const_value(self.tcx, val, self.used_items);
     }
 
     fn visit_terminator(&mut self, terminator: &mir::Terminator<'tcx>, location: Location) {
@@ -852,34 +930,41 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirUsedCollector<'a, 'tcx> {
         let push_mono_lang_item = |this: &mut Self, lang_item: LangItem| {
             let instance = Instance::mono(tcx, tcx.require_lang_item(lang_item, Some(source)));
             if should_codegen_locally(tcx, &instance) {
-                this.output.push(create_fn_mono_item(tcx, instance, source));
+                this.used_items.push(create_fn_mono_item(tcx, instance, source));
             }
         };
 
         match terminator.kind {
             mir::TerminatorKind::Call { ref func, ref args, ref fn_span, .. } => {
                 let callee_ty = func.ty(self.body, tcx);
+                // *Before* monomorphizing, record that we already handled this mention.
+                self.used_mentioned_items.insert(MentionedItem::Fn(callee_ty));
                 let callee_ty = self.monomorphize(callee_ty);
                 self.check_fn_args_move_size(callee_ty, args, *fn_span, location);
-                visit_fn_use(self.tcx, callee_ty, true, source, &mut self.output)
+                visit_fn_use(self.tcx, callee_ty, true, source, &mut self.used_items)
             }
             mir::TerminatorKind::Drop { ref place, .. } => {
                 let ty = place.ty(self.body, self.tcx).ty;
+                // *Before* monomorphizing, record that we already handled this mention.
+                self.used_mentioned_items.insert(MentionedItem::Drop(ty));
                 let ty = self.monomorphize(ty);
-                visit_drop_use(self.tcx, ty, true, source, self.output);
+                visit_drop_use(self.tcx, ty, true, source, self.used_items);
             }
             mir::TerminatorKind::InlineAsm { ref operands, .. } => {
                 for op in operands {
                     match *op {
                         mir::InlineAsmOperand::SymFn { ref value } => {
-                            let fn_ty = self.monomorphize(value.const_.ty());
-                            visit_fn_use(self.tcx, fn_ty, false, source, self.output);
+                            let fn_ty = value.const_.ty();
+                            // *Before* monomorphizing, record that we already handled this mention.
+                            self.used_mentioned_items.insert(MentionedItem::Fn(fn_ty));
+                            let fn_ty = self.monomorphize(fn_ty);
+                            visit_fn_use(self.tcx, fn_ty, false, source, self.used_items);
                         }
                         mir::InlineAsmOperand::SymStatic { def_id } => {
                             let instance = Instance::mono(self.tcx, def_id);
                             if should_codegen_locally(self.tcx, &instance) {
                                 trace!("collecting asm sym static {:?}", def_id);
-                                self.output.push(respan(source, MonoItem::Static(def_id)));
+                                self.used_items.push(respan(source, MonoItem::Static(def_id)));
                             }
                         }
                         _ => {}
@@ -936,6 +1021,8 @@ fn visit_drop_use<'tcx>(
     visit_instance_use(tcx, instance, is_direct_call, source, output);
 }
 
+/// For every call of this function in the visitor, make sure there is a matching call in the
+/// `mentioned_items` pass!
 fn visit_fn_use<'tcx>(
     tcx: TyCtxt<'tcx>,
     ty: Ty<'tcx>,
@@ -1197,34 +1284,225 @@ fn create_mono_items_for_vtable_methods<'tcx>(
 ) {
     assert!(!trait_ty.has_escaping_bound_vars() && !impl_ty.has_escaping_bound_vars());
 
-    if let ty::Dynamic(trait_ty, ..) = trait_ty.kind() {
-        if let Some(principal) = trait_ty.principal() {
-            let poly_trait_ref = principal.with_self_ty(tcx, impl_ty);
-            assert!(!poly_trait_ref.has_escaping_bound_vars());
-
-            // Walk all methods of the trait, including those of its supertraits
-            let entries = tcx.vtable_entries(poly_trait_ref);
-            let methods = entries
-                .iter()
-                .filter_map(|entry| match entry {
-                    VtblEntry::MetadataDropInPlace
-                    | VtblEntry::MetadataSize
-                    | VtblEntry::MetadataAlign
-                    | VtblEntry::Vacant => None,
-                    VtblEntry::TraitVPtr(_) => {
-                        // all super trait items already covered, so skip them.
-                        None
-                    }
-                    VtblEntry::Method(instance) => {
-                        Some(*instance).filter(|instance| should_codegen_locally(tcx, instance))
+    let ty::Dynamic(trait_ty, ..) = trait_ty.kind() else {
+        bug!("create_mono_items_for_vtable_methods: {trait_ty:?} not a trait type");
+    };
+    if let Some(principal) = trait_ty.principal() {
+        let poly_trait_ref = principal.with_self_ty(tcx, impl_ty);
+        assert!(!poly_trait_ref.has_escaping_bound_vars());
+
+        // Walk all methods of the trait, including those of its supertraits
+        let entries = tcx.vtable_entries(poly_trait_ref);
+        debug!(?entries);
+        let methods = entries
+            .iter()
+            .filter_map(|entry| match entry {
+                VtblEntry::MetadataDropInPlace
+                | VtblEntry::MetadataSize
+                | VtblEntry::MetadataAlign
+                | VtblEntry::Vacant => None,
+                VtblEntry::TraitVPtr(_) => {
+                    // all super trait items already covered, so skip them.
+                    None
+                }
+                VtblEntry::Method(instance) => {
+                    Some(*instance).filter(|instance| should_codegen_locally(tcx, instance))
+                }
+            })
+            .map(|item| create_fn_mono_item(tcx, item, source));
+        output.extend(methods);
+    }
+
+    // Also add the destructor.
+    visit_drop_use(tcx, impl_ty, false, source, output);
+}
+
+/// Scans the CTFE alloc in order to find function pointers and statics that must be monomorphized.
+fn collect_alloc<'tcx>(tcx: TyCtxt<'tcx>, alloc_id: AllocId, output: &mut MonoItems<'tcx>) {
+    match tcx.global_alloc(alloc_id) {
+        GlobalAlloc::Static(def_id) => {
+            assert!(!tcx.is_thread_local_static(def_id));
+            let instance = Instance::mono(tcx, def_id);
+            if should_codegen_locally(tcx, &instance) {
+                trace!("collecting static {:?}", def_id);
+                output.push(dummy_spanned(MonoItem::Static(def_id)));
+            }
+        }
+        GlobalAlloc::Memory(alloc) => {
+            trace!("collecting {:?} with {:#?}", alloc_id, alloc);
+            let ptrs = alloc.inner().provenance().ptrs();
+            // avoid `ensure_sufficient_stack` in the common case of "no pointers"
+            if !ptrs.is_empty() {
+                rustc_data_structures::stack::ensure_sufficient_stack(move || {
+                    for &prov in ptrs.values() {
+                        collect_alloc(tcx, prov.alloc_id(), output);
                     }
-                })
-                .map(|item| create_fn_mono_item(tcx, item, source));
-            output.extend(methods);
+                });
+            }
+        }
+        GlobalAlloc::Function(fn_instance) => {
+            if should_codegen_locally(tcx, &fn_instance) {
+                trace!("collecting {:?} with {:#?}", alloc_id, fn_instance);
+                output.push(create_fn_mono_item(tcx, fn_instance, DUMMY_SP));
+            }
+        }
+        GlobalAlloc::VTable(ty, trait_ref) => {
+            let alloc_id = tcx.vtable_allocation((ty, trait_ref));
+            collect_alloc(tcx, alloc_id, output)
         }
+    }
+}
 
-        // Also add the destructor.
-        visit_drop_use(tcx, impl_ty, false, source, output);
+fn assoc_fn_of_type<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, fn_ident: Ident) -> Option<DefId> {
+    for impl_def_id in tcx.inherent_impls(def_id).ok()? {
+        if let Some(new) = tcx.associated_items(impl_def_id).find_by_name_and_kind(
+            tcx,
+            fn_ident,
+            AssocKind::Fn,
+            def_id,
+        ) {
+            return Some(new.def_id);
+        }
+    }
+    return None;
+}
+
+fn build_skip_move_check_fns(tcx: TyCtxt<'_>) -> Vec<DefId> {
+    let fns = [
+        (tcx.lang_items().owned_box(), "new"),
+        (tcx.get_diagnostic_item(sym::Rc), "new"),
+        (tcx.get_diagnostic_item(sym::Arc), "new"),
+    ];
+    fns.into_iter()
+        .filter_map(|(def_id, fn_name)| {
+            def_id.and_then(|def_id| assoc_fn_of_type(tcx, def_id, Ident::from_str(fn_name)))
+        })
+        .collect::<Vec<_>>()
+}
+
+/// Scans the MIR in order to find function calls, closures, and drop-glue.
+///
+/// Anything that's found is added to `output`. Furthermore the "mentioned items" of the MIR are returned.
+#[instrument(skip(tcx, used_items, mentioned_items), level = "debug")]
+fn collect_items_of_instance<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    instance: Instance<'tcx>,
+    used_items: &mut MonoItems<'tcx>,
+    mentioned_items: &mut MonoItems<'tcx>,
+    mode: CollectionMode,
+) {
+    let body = tcx.instance_mir(instance.def);
+    // Naively, in "used" collection mode, all functions get added to *both* `used_items` and
+    // `mentioned_items`. Mentioned items processing will then notice that they have already been
+    // visited, but at that point each mentioned item has been monomorphized, added to the
+    // `mentioned_items` worklist, and checked in the global set of visited items. To remove that
+    // overhead, we have a special optimization that avoids adding items to `mentioned_items` when
+    // they are already added in `used_items`. We could just scan `used_items`, but that's a linear
+    // scan and not very efficient. Furthermore we can only do that *after* monomorphizing the
+    // mentioned item. So instead we collect all pre-monomorphized `MentionedItem` that were already
+    // added to `used_items` in a hash set, which can efficiently query in the
+    // `body.mentioned_items` loop below without even having to monomorphize the item.
+    let mut used_mentioned_items = FxHashSet::<MentionedItem<'tcx>>::default();
+    let mut collector = MirUsedCollector {
+        tcx,
+        body,
+        used_items,
+        used_mentioned_items: &mut used_mentioned_items,
+        instance,
+        move_size_spans: vec![],
+        visiting_call_terminator: false,
+        skip_move_check_fns: None,
+    };
+
+    if mode == CollectionMode::UsedItems {
+        // Visit everything. Here we rely on the visitor also visiting `required_consts`, so that we
+        // evaluate them and abort compilation if any of them errors.
+        collector.visit_body(body);
+    } else {
+        // We only need to evaluate all constants, but can ignore the rest of the MIR.
+        for const_op in &body.required_consts {
+            if let Some(val) = collector.eval_constant(const_op) {
+                collect_const_value(tcx, val, mentioned_items);
+            }
+        }
+    }
+
+    // Always gather mentioned items. We try to avoid processing items that we have already added to
+    // `used_items` above.
+    for item in &body.mentioned_items {
+        if !collector.used_mentioned_items.contains(&item.node) {
+            let item_mono = collector.monomorphize(item.node);
+            visit_mentioned_item(tcx, &item_mono, item.span, mentioned_items);
+        }
+    }
+}
+
+/// `item` must be already monomorphized.
+#[instrument(skip(tcx, span, output), level = "debug")]
+fn visit_mentioned_item<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    item: &MentionedItem<'tcx>,
+    span: Span,
+    output: &mut MonoItems<'tcx>,
+) {
+    match *item {
+        MentionedItem::Fn(ty) => {
+            if let ty::FnDef(def_id, args) = *ty.kind() {
+                let instance =
+                    Instance::expect_resolve(tcx, ty::ParamEnv::reveal_all(), def_id, args);
+                // `visit_instance_use` was written for "used" item collection but works just as well
+                // for "mentioned" item collection.
+                // We can set `is_direct_call`; that just means we'll skip a bunch of shims that anyway
+                // can't have their own failing constants.
+                visit_instance_use(tcx, instance, /*is_direct_call*/ true, span, output);
+            }
+        }
+        MentionedItem::Drop(ty) => {
+            visit_drop_use(tcx, ty, /*is_direct_call*/ true, span, output);
+        }
+        MentionedItem::UnsizeCast { source_ty, target_ty } => {
+            let (source_ty, target_ty) =
+                find_vtable_types_for_unsizing(tcx.at(span), source_ty, target_ty);
+            // This could also be a different Unsize instruction, like
+            // from a fixed sized array to a slice. But we are only
+            // interested in things that produce a vtable.
+            if (target_ty.is_trait() && !source_ty.is_trait())
+                || (target_ty.is_dyn_star() && !source_ty.is_dyn_star())
+            {
+                create_mono_items_for_vtable_methods(tcx, target_ty, source_ty, span, output);
+            }
+        }
+        MentionedItem::Closure(source_ty) => {
+            if let ty::Closure(def_id, args) = *source_ty.kind() {
+                let instance =
+                    Instance::resolve_closure(tcx, def_id, args, ty::ClosureKind::FnOnce);
+                if should_codegen_locally(tcx, &instance) {
+                    output.push(create_fn_mono_item(tcx, instance, span));
+                }
+            } else {
+                bug!()
+            }
+        }
+    }
+}
+
+#[instrument(skip(tcx, output), level = "debug")]
+fn collect_const_value<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    value: mir::ConstValue<'tcx>,
+    output: &mut MonoItems<'tcx>,
+) {
+    match value {
+        mir::ConstValue::Scalar(Scalar::Ptr(ptr, _size)) => {
+            collect_alloc(tcx, ptr.provenance.alloc_id(), output)
+        }
+        mir::ConstValue::Indirect { alloc_id, .. } => collect_alloc(tcx, alloc_id, output),
+        mir::ConstValue::Slice { data, meta: _ } => {
+            for &prov in data.inner().provenance().ptrs().values() {
+                collect_alloc(tcx, prov.alloc_id(), output);
+            }
+        }
+        _ => {}
     }
 }
 
@@ -1232,9 +1510,47 @@ fn create_mono_items_for_vtable_methods<'tcx>(
 // Root Collection
 //=-----------------------------------------------------------------------------
 
+// Find all non-generic items by walking the HIR. These items serve as roots to
+// start monomorphizing from.
+#[instrument(skip(tcx, mode), level = "debug")]
+fn collect_roots(tcx: TyCtxt<'_>, mode: MonoItemCollectionStrategy) -> Vec<MonoItem<'_>> {
+    debug!("collecting roots");
+    let mut roots = Vec::new();
+
+    {
+        let entry_fn = tcx.entry_fn(());
+
+        debug!("collect_roots: entry_fn = {:?}", entry_fn);
+
+        let mut collector = RootCollector { tcx, strategy: mode, entry_fn, output: &mut roots };
+
+        let crate_items = tcx.hir_crate_items(());
+
+        for id in crate_items.free_items() {
+            collector.process_item(id);
+        }
+
+        for id in crate_items.impl_items() {
+            collector.process_impl_item(id);
+        }
+
+        collector.push_extra_entry_roots();
+    }
+
+    // We can only codegen items that are instantiable - items all of
+    // whose predicates hold. Luckily, items that aren't instantiable
+    // can't actually be used, so we can just skip codegenning them.
+    roots
+        .into_iter()
+        .filter_map(|Spanned { node: mono_item, .. }| {
+            mono_item.is_instantiable(tcx).then_some(mono_item)
+        })
+        .collect()
+}
+
 struct RootCollector<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
-    mode: MonoItemCollectionMode,
+    strategy: MonoItemCollectionStrategy,
     output: &'a mut MonoItems<'tcx>,
     entry_fn: Option<(DefId, EntryFnType)>,
 }
@@ -1243,7 +1559,7 @@ impl<'v> RootCollector<'_, 'v> {
     fn process_item(&mut self, id: hir::ItemId) {
         match self.tcx.def_kind(id.owner_id) {
             DefKind::Enum | DefKind::Struct | DefKind::Union => {
-                if self.mode == MonoItemCollectionMode::Eager
+                if self.strategy == MonoItemCollectionStrategy::Eager
                     && self.tcx.generics_of(id.owner_id).count() == 0
                 {
                     debug!("RootCollector: ADT drop-glue for `{id:?}`",);
@@ -1274,7 +1590,7 @@ impl<'v> RootCollector<'_, 'v> {
                 }
             }
             DefKind::Impl { .. } => {
-                if self.mode == MonoItemCollectionMode::Eager {
+                if self.strategy == MonoItemCollectionStrategy::Eager {
                     create_mono_items_for_default_impls(self.tcx, id, self.output);
                 }
             }
@@ -1293,9 +1609,9 @@ impl<'v> RootCollector<'_, 'v> {
 
     fn is_root(&self, def_id: LocalDefId) -> bool {
         !self.tcx.generics_of(def_id).requires_monomorphization(self.tcx)
-            && match self.mode {
-                MonoItemCollectionMode::Eager => true,
-                MonoItemCollectionMode::Lazy => {
+            && match self.strategy {
+                MonoItemCollectionStrategy::Eager => true,
+                MonoItemCollectionStrategy::Lazy => {
                     self.entry_fn.and_then(|(id, _)| id.as_local()) == Some(def_id)
                         || self.tcx.is_reachable_non_generic(def_id)
                         || self
@@ -1428,108 +1744,47 @@ fn create_mono_items_for_default_impls<'tcx>(
     }
 }
 
-/// Scans the CTFE alloc in order to find function pointers and statics that must be monomorphized.
-fn collect_alloc<'tcx>(tcx: TyCtxt<'tcx>, alloc_id: AllocId, output: &mut MonoItems<'tcx>) {
-    match tcx.global_alloc(alloc_id) {
-        GlobalAlloc::Static(def_id) => {
-            assert!(!tcx.is_thread_local_static(def_id));
-            let instance = Instance::mono(tcx, def_id);
-            if should_codegen_locally(tcx, &instance) {
-                trace!("collecting static {:?}", def_id);
-                output.push(dummy_spanned(MonoItem::Static(def_id)));
-            }
-        }
-        GlobalAlloc::Memory(alloc) => {
-            trace!("collecting {:?} with {:#?}", alloc_id, alloc);
-            let ptrs = alloc.inner().provenance().ptrs();
-            // avoid `ensure_sufficient_stack` in the common case of "no pointers"
-            if !ptrs.is_empty() {
-                rustc_data_structures::stack::ensure_sufficient_stack(move || {
-                    for &prov in ptrs.values() {
-                        collect_alloc(tcx, prov.alloc_id(), output);
-                    }
-                });
-            }
-        }
-        GlobalAlloc::Function(fn_instance) => {
-            if should_codegen_locally(tcx, &fn_instance) {
-                trace!("collecting {:?} with {:#?}", alloc_id, fn_instance);
-                output.push(create_fn_mono_item(tcx, fn_instance, DUMMY_SP));
-            }
-        }
-        GlobalAlloc::VTable(ty, trait_ref) => {
-            let alloc_id = tcx.vtable_allocation((ty, trait_ref));
-            collect_alloc(tcx, alloc_id, output)
-        }
-    }
-}
+//=-----------------------------------------------------------------------------
+// Top-level entry point, tying it all together
+//=-----------------------------------------------------------------------------
 
-fn assoc_fn_of_type<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId, fn_ident: Ident) -> Option<DefId> {
-    for impl_def_id in tcx.inherent_impls(def_id).ok()? {
-        if let Some(new) = tcx.associated_items(impl_def_id).find_by_name_and_kind(
-            tcx,
-            fn_ident,
-            AssocKind::Fn,
-            def_id,
-        ) {
-            return Some(new.def_id);
-        }
-    }
-    return None;
-}
+#[instrument(skip(tcx, strategy), level = "debug")]
+pub fn collect_crate_mono_items(
+    tcx: TyCtxt<'_>,
+    strategy: MonoItemCollectionStrategy,
+) -> (FxHashSet<MonoItem<'_>>, UsageMap<'_>) {
+    let _prof_timer = tcx.prof.generic_activity("monomorphization_collector");
 
-fn build_skip_move_check_fns(tcx: TyCtxt<'_>) -> Vec<DefId> {
-    let fns = [
-        (tcx.lang_items().owned_box(), "new"),
-        (tcx.get_diagnostic_item(sym::Rc), "new"),
-        (tcx.get_diagnostic_item(sym::Arc), "new"),
-    ];
-    fns.into_iter()
-        .filter_map(|(def_id, fn_name)| {
-            def_id.and_then(|def_id| assoc_fn_of_type(tcx, def_id, Ident::from_str(fn_name)))
-        })
-        .collect::<Vec<_>>()
-}
+    let roots = tcx
+        .sess
+        .time("monomorphization_collector_root_collections", || collect_roots(tcx, strategy));
 
-/// Scans the MIR in order to find function calls, closures, and drop-glue.
-#[instrument(skip(tcx, output), level = "debug")]
-fn collect_used_items<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    instance: Instance<'tcx>,
-    output: &mut MonoItems<'tcx>,
-) {
-    let body = tcx.instance_mir(instance.def);
+    debug!("building mono item graph, beginning at roots");
 
-    // Here we rely on the visitor also visiting `required_consts`, so that we evaluate them
-    // and abort compilation if any of them errors.
-    MirUsedCollector {
-        tcx,
-        body: body,
-        output,
-        instance,
-        move_size_spans: vec![],
-        visiting_call_terminator: false,
-        skip_move_check_fns: None,
-    }
-    .visit_body(body);
-}
+    let mut state = SharedState {
+        visited: MTLock::new(FxHashSet::default()),
+        mentioned: MTLock::new(FxHashSet::default()),
+        usage_map: MTLock::new(UsageMap::new()),
+    };
+    let recursion_limit = tcx.recursion_limit();
 
-#[instrument(skip(tcx, output), level = "debug")]
-fn collect_const_value<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    value: mir::ConstValue<'tcx>,
-    output: &mut MonoItems<'tcx>,
-) {
-    match value {
-        mir::ConstValue::Scalar(Scalar::Ptr(ptr, _size)) => {
-            collect_alloc(tcx, ptr.provenance.alloc_id(), output)
-        }
-        mir::ConstValue::Indirect { alloc_id, .. } => collect_alloc(tcx, alloc_id, output),
-        mir::ConstValue::Slice { data, meta: _ } => {
-            for &prov in data.inner().provenance().ptrs().values() {
-                collect_alloc(tcx, prov.alloc_id(), output);
-            }
-        }
-        _ => {}
+    {
+        let state: LRef<'_, _> = &mut state;
+
+        tcx.sess.time("monomorphization_collector_graph_walk", || {
+            par_for_each_in(roots, |root| {
+                let mut recursion_depths = DefIdMap::default();
+                collect_items_rec(
+                    tcx,
+                    dummy_spanned(root),
+                    state,
+                    &mut recursion_depths,
+                    recursion_limit,
+                    CollectionMode::UsedItems,
+                );
+            });
+        });
     }
+
+    (state.visited.into_inner(), state.usage_map.into_inner())
 }
diff --git a/compiler/rustc_monomorphize/src/partitioning.rs b/compiler/rustc_monomorphize/src/partitioning.rs
index 15041b9cd41..5a92657cb40 100644
--- a/compiler/rustc_monomorphize/src/partitioning.rs
+++ b/compiler/rustc_monomorphize/src/partitioning.rs
@@ -117,7 +117,7 @@ use rustc_session::CodegenUnits;
 use rustc_span::symbol::Symbol;
 
 use crate::collector::UsageMap;
-use crate::collector::{self, MonoItemCollectionMode};
+use crate::collector::{self, MonoItemCollectionStrategy};
 use crate::errors::{CouldntDumpMonoStats, SymbolAlreadyDefined, UnknownCguCollectionMode};
 
 struct PartitioningCx<'a, 'tcx> {
@@ -1087,30 +1087,30 @@ where
 }
 
 fn collect_and_partition_mono_items(tcx: TyCtxt<'_>, (): ()) -> (&DefIdSet, &[CodegenUnit<'_>]) {
-    let collection_mode = match tcx.sess.opts.unstable_opts.print_mono_items {
+    let collection_strategy = match tcx.sess.opts.unstable_opts.print_mono_items {
         Some(ref s) => {
             let mode = s.to_lowercase();
             let mode = mode.trim();
             if mode == "eager" {
-                MonoItemCollectionMode::Eager
+                MonoItemCollectionStrategy::Eager
             } else {
                 if mode != "lazy" {
                     tcx.dcx().emit_warn(UnknownCguCollectionMode { mode });
                 }
 
-                MonoItemCollectionMode::Lazy
+                MonoItemCollectionStrategy::Lazy
             }
         }
         None => {
             if tcx.sess.link_dead_code() {
-                MonoItemCollectionMode::Eager
+                MonoItemCollectionStrategy::Eager
             } else {
-                MonoItemCollectionMode::Lazy
+                MonoItemCollectionStrategy::Lazy
             }
         }
     };
 
-    let (items, usage_map) = collector::collect_crate_mono_items(tcx, collection_mode);
+    let (items, usage_map) = collector::collect_crate_mono_items(tcx, collection_strategy);
 
     // If there was an error during collection (e.g. from one of the constants we evaluated),
     // then we stop here. This way codegen does not have to worry about failing constants.
diff --git a/compiler/rustc_parse/messages.ftl b/compiler/rustc_parse/messages.ftl
index a100e2d47bb..e1d26f090e0 100644
--- a/compiler/rustc_parse/messages.ftl
+++ b/compiler/rustc_parse/messages.ftl
@@ -390,8 +390,6 @@ parse_invalid_dyn_keyword = invalid `dyn` keyword
 parse_invalid_expression_in_let_else = a `{$operator}` expression cannot be directly assigned in `let...else`
 parse_invalid_identifier_with_leading_number = identifiers cannot start with a number
 
-parse_invalid_interpolated_expression = invalid interpolated expression
-
 parse_invalid_literal_suffix_on_tuple_index = suffixes on a tuple index are invalid
     .label = invalid suffix `{$suffix}`
     .tuple_exception_line_1 = `{$suffix}` is *temporarily* accepted on tuple index fields as it was incorrectly accepted on stable for a few releases
diff --git a/compiler/rustc_parse/src/errors.rs b/compiler/rustc_parse/src/errors.rs
index 32b56bb7e87..5cad3a568ee 100644
--- a/compiler/rustc_parse/src/errors.rs
+++ b/compiler/rustc_parse/src/errors.rs
@@ -851,13 +851,6 @@ pub(crate) struct StructLiteralNotAllowedHereSugg {
 }
 
 #[derive(Diagnostic)]
-#[diag(parse_invalid_interpolated_expression)]
-pub(crate) struct InvalidInterpolatedExpression {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(parse_invalid_literal_suffix_on_tuple_index)]
 pub(crate) struct InvalidLiteralSuffixOnTupleIndex {
     #[primary_span]
diff --git a/compiler/rustc_parse/src/parser/attr.rs b/compiler/rustc_parse/src/parser/attr.rs
index d08c50b5b06..ab5f51eedc3 100644
--- a/compiler/rustc_parse/src/parser/attr.rs
+++ b/compiler/rustc_parse/src/parser/attr.rs
@@ -3,11 +3,12 @@ use crate::errors::{
     SuffixedLiteralInAttribute,
 };
 use crate::fluent_generated as fluent;
+use crate::maybe_whole;
 
 use super::{AttrWrapper, Capturing, FnParseMode, ForceCollect, Parser, PathStyle};
 use rustc_ast as ast;
 use rustc_ast::attr;
-use rustc_ast::token::{self, Delimiter, Nonterminal};
+use rustc_ast::token::{self, Delimiter};
 use rustc_errors::{codes::*, Diag, PResult};
 use rustc_span::{sym, BytePos, Span};
 use thin_vec::ThinVec;
@@ -251,25 +252,15 @@ impl<'a> Parser<'a> {
     ///     PATH `=` UNSUFFIXED_LIT
     /// The delimiters or `=` are still put into the resulting token stream.
     pub fn parse_attr_item(&mut self, capture_tokens: bool) -> PResult<'a, ast::AttrItem> {
-        let item = match &self.token.kind {
-            token::Interpolated(nt) => match &nt.0 {
-                Nonterminal::NtMeta(item) => Some(item.clone().into_inner()),
-                _ => None,
-            },
-            _ => None,
+        maybe_whole!(self, NtMeta, |attr| attr.into_inner());
+
+        let do_parse = |this: &mut Self| {
+            let path = this.parse_path(PathStyle::Mod)?;
+            let args = this.parse_attr_args()?;
+            Ok(ast::AttrItem { path, args, tokens: None })
         };
-        Ok(if let Some(item) = item {
-            self.bump();
-            item
-        } else {
-            let do_parse = |this: &mut Self| {
-                let path = this.parse_path(PathStyle::Mod)?;
-                let args = this.parse_attr_args()?;
-                Ok(ast::AttrItem { path, args, tokens: None })
-            };
-            // Attr items don't have attributes
-            if capture_tokens { self.collect_tokens_no_attrs(do_parse) } else { do_parse(self) }?
-        })
+        // Attr items don't have attributes
+        if capture_tokens { self.collect_tokens_no_attrs(do_parse) } else { do_parse(self) }
     }
 
     /// Parses attributes that appear after the opening of an item. These should
@@ -371,22 +362,18 @@ impl<'a> Parser<'a> {
     /// meta_item_inner : (meta_item | UNSUFFIXED_LIT) (',' meta_item_inner)? ;
     /// ```
     pub fn parse_meta_item(&mut self) -> PResult<'a, ast::MetaItem> {
-        let nt_meta = match &self.token.kind {
-            token::Interpolated(nt) => match &nt.0 {
-                token::NtMeta(e) => Some(e.clone()),
-                _ => None,
-            },
-            _ => None,
-        };
-
-        if let Some(item) = nt_meta {
-            match item.meta(item.path.span) {
+        // We can't use `maybe_whole` here because it would bump in the `None`
+        // case, which we don't want.
+        if let token::Interpolated(nt) = &self.token.kind
+            && let token::NtMeta(attr_item) = &nt.0
+        {
+            match attr_item.meta(attr_item.path.span) {
                 Some(meta) => {
                     self.bump();
                     return Ok(meta);
                 }
                 None => self.unexpected()?,
-            };
+            }
         }
 
         let lo = self.token.span;
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index 136145dd182..fe17eba0d7b 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -11,7 +11,7 @@ use crate::errors;
 use crate::maybe_recover_from_interpolated_ty_qpath;
 use ast::mut_visit::{noop_visit_expr, MutVisitor};
 use ast::token::IdentIsRaw;
-use ast::{CoroutineKind, ForLoopKind, GenBlockKind, Pat, Path, PathSegment};
+use ast::{CoroutineKind, ForLoopKind, GenBlockKind, MatchKind, Pat, Path, PathSegment};
 use core::mem;
 use core::ops::ControlFlow;
 use rustc_ast::ptr::P;
@@ -1379,6 +1379,13 @@ impl<'a> Parser<'a> {
             return Ok(self.mk_await_expr(self_arg, lo));
         }
 
+        // Post-fix match
+        if self.eat_keyword(kw::Match) {
+            let match_span = self.prev_token.span;
+            self.psess.gated_spans.gate(sym::postfix_match, match_span);
+            return self.parse_match_block(lo, match_span, self_arg, MatchKind::Postfix);
+        }
+
         let fn_span_lo = self.token.span;
         let mut seg = self.parse_path_segment(PathStyle::Expr, None)?;
         self.check_trailing_angle_brackets(&seg, &[&token::OpenDelim(Delimiter::Parenthesis)]);
@@ -1939,11 +1946,11 @@ impl<'a> Parser<'a> {
     /// Parse `builtin # ident(args,*)`.
     fn parse_expr_builtin(&mut self) -> PResult<'a, P<Expr>> {
         self.parse_builtin(|this, lo, ident| {
-            if ident.name == sym::offset_of {
-                return Ok(Some(this.parse_expr_offset_of(lo)?));
-            }
-
-            Ok(None)
+            Ok(match ident.name {
+                sym::offset_of => Some(this.parse_expr_offset_of(lo)?),
+                sym::type_ascribe => Some(this.parse_expr_type_ascribe(lo)?),
+                _ => None,
+            })
         })
     }
 
@@ -1978,6 +1985,7 @@ impl<'a> Parser<'a> {
         ret
     }
 
+    /// Built-in macro for `offset_of!` expressions.
     pub(crate) fn parse_expr_offset_of(&mut self, lo: Span) -> PResult<'a, P<Expr>> {
         let container = self.parse_ty()?;
         self.expect(&TokenKind::Comma)?;
@@ -2007,6 +2015,15 @@ impl<'a> Parser<'a> {
         Ok(self.mk_expr(span, ExprKind::OffsetOf(container, fields)))
     }
 
+    /// Built-in macro for type ascription expressions.
+    pub(crate) fn parse_expr_type_ascribe(&mut self, lo: Span) -> PResult<'a, P<Expr>> {
+        let expr = self.parse_expr()?;
+        self.expect(&token::Comma)?;
+        let ty = self.parse_ty()?;
+        let span = lo.to(self.token.span);
+        Ok(self.mk_expr(span, ExprKind::Type(expr, ty)))
+    }
+
     /// Returns a string literal if the next token is a string literal.
     /// In case of error returns `Some(lit)` if the next token is a literal with a wrong kind,
     /// and returns `None` if the next token is not literal at all.
@@ -2043,16 +2060,6 @@ impl<'a> Parser<'a> {
         &mut self,
         mk_lit_char: impl FnOnce(Symbol, Span) -> L,
     ) -> PResult<'a, L> {
-        if let token::Interpolated(nt) = &self.token.kind
-            && let token::NtExpr(e) | token::NtLiteral(e) = &nt.0
-            && matches!(e.kind, ExprKind::Err(_))
-        {
-            let mut err = self
-                .dcx()
-                .create_err(errors::InvalidInterpolatedExpression { span: self.token.span });
-            err.downgrade_to_delayed_bug();
-            return Err(err);
-        }
         let token = self.token.clone();
         let err = |self_: &Self| {
             let msg = format!("unexpected token: {}", super::token_descr(&token));
@@ -2894,8 +2901,20 @@ impl<'a> Parser<'a> {
     /// Parses a `match ... { ... }` expression (`match` token already eaten).
     fn parse_expr_match(&mut self) -> PResult<'a, P<Expr>> {
         let match_span = self.prev_token.span;
-        let lo = self.prev_token.span;
         let scrutinee = self.parse_expr_res(Restrictions::NO_STRUCT_LITERAL, None)?;
+
+        self.parse_match_block(match_span, match_span, scrutinee, MatchKind::Prefix)
+    }
+
+    /// Parses the block of a `match expr { ... }` or a `expr.match { ... }`
+    /// expression. This is after the match token and scrutinee are eaten
+    fn parse_match_block(
+        &mut self,
+        lo: Span,
+        match_span: Span,
+        scrutinee: P<Expr>,
+        match_kind: MatchKind,
+    ) -> PResult<'a, P<Expr>> {
         if let Err(mut e) = self.expect(&token::OpenDelim(Delimiter::Brace)) {
             if self.token == token::Semi {
                 e.span_suggestion_short(
@@ -2938,7 +2957,7 @@ impl<'a> Parser<'a> {
                     });
                     return Ok(self.mk_expr_with_attrs(
                         span,
-                        ExprKind::Match(scrutinee, arms),
+                        ExprKind::Match(scrutinee, arms, match_kind),
                         attrs,
                     ));
                 }
@@ -2946,7 +2965,7 @@ impl<'a> Parser<'a> {
         }
         let hi = self.token.span;
         self.bump();
-        Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms), attrs))
+        Ok(self.mk_expr_with_attrs(lo.to(hi), ExprKind::Match(scrutinee, arms, match_kind), attrs))
     }
 
     /// Attempt to recover from match arm body with statements and no surrounding braces.
@@ -3955,7 +3974,7 @@ impl MutVisitor for CondChecker<'_> {
             | ExprKind::While(_, _, _)
             | ExprKind::ForLoop { .. }
             | ExprKind::Loop(_, _, _)
-            | ExprKind::Match(_, _)
+            | ExprKind::Match(_, _, _)
             | ExprKind::Closure(_)
             | ExprKind::Block(_, _)
             | ExprKind::Gen(_, _, _)
diff --git a/compiler/rustc_parse/src/parser/item.rs b/compiler/rustc_parse/src/parser/item.rs
index 18d210eacfa..d54eb8dc4c9 100644
--- a/compiler/rustc_parse/src/parser/item.rs
+++ b/compiler/rustc_parse/src/parser/item.rs
@@ -6,6 +6,7 @@ use super::{
 };
 use crate::errors::{self, MacroExpandsToAdtField};
 use crate::fluent_generated as fluent;
+use crate::maybe_whole;
 use ast::token::IdentIsRaw;
 use rustc_ast::ast::*;
 use rustc_ast::ptr::P;
@@ -115,17 +116,10 @@ impl<'a> Parser<'a> {
         fn_parse_mode: FnParseMode,
         force_collect: ForceCollect,
     ) -> PResult<'a, Option<Item>> {
-        // Don't use `maybe_whole` so that we have precise control
-        // over when we bump the parser
-        if let token::Interpolated(nt) = &self.token.kind
-            && let token::NtItem(item) = &nt.0
-        {
-            let mut item = item.clone();
-            self.bump();
-
+        maybe_whole!(self, NtItem, |item| {
             attrs.prepend_to_nt_inner(&mut item.attrs);
-            return Ok(Some(item.into_inner()));
-        };
+            Some(item.into_inner())
+        });
 
         let item =
             self.collect_tokens_trailing_token(attrs, force_collect, |this: &mut Self, attrs| {
diff --git a/compiler/rustc_parse/src/parser/mod.rs b/compiler/rustc_parse/src/parser/mod.rs
index 125e77d8ee7..de83528b52c 100644
--- a/compiler/rustc_parse/src/parser/mod.rs
+++ b/compiler/rustc_parse/src/parser/mod.rs
@@ -20,7 +20,7 @@ pub use pat::{CommaRecoveryMode, RecoverColon, RecoverComma};
 pub use path::PathStyle;
 
 use rustc_ast::ptr::P;
-use rustc_ast::token::{self, Delimiter, Nonterminal, Token, TokenKind};
+use rustc_ast::token::{self, Delimiter, Token, TokenKind};
 use rustc_ast::tokenstream::{AttributesData, DelimSpacing, DelimSpan, Spacing};
 use rustc_ast::tokenstream::{TokenStream, TokenTree, TokenTreeCursor};
 use rustc_ast::util::case::Case;
@@ -93,12 +93,13 @@ pub enum TrailingToken {
 #[macro_export]
 macro_rules! maybe_whole {
     ($p:expr, $constructor:ident, |$x:ident| $e:expr) => {
-        if let token::Interpolated(nt) = &$p.token.kind {
-            if let token::$constructor(x) = &nt.0 {
-                let $x = x.clone();
-                $p.bump();
-                return Ok($e);
-            }
+        if let token::Interpolated(nt) = &$p.token.kind
+            && let token::$constructor(x) = &nt.0
+        {
+            #[allow(unused_mut)]
+            let mut $x = x.clone();
+            $p.bump();
+            return Ok($e);
         }
     };
 }
@@ -449,6 +450,7 @@ impl<'a> Parser<'a> {
         parser
     }
 
+    #[inline]
     pub fn recovery(mut self, recovery: Recovery) -> Self {
         self.recovery = recovery;
         self
@@ -461,6 +463,7 @@ impl<'a> Parser<'a> {
     ///
     /// Technically, this only needs to restrict eager recovery by doing lookahead at more tokens.
     /// But making the distinction is very subtle, and simply forbidding all recovery is a lot simpler to uphold.
+    #[inline]
     fn may_recover(&self) -> bool {
         matches!(self.recovery, Recovery::Allowed)
     }
@@ -548,6 +551,7 @@ impl<'a> Parser<'a> {
     ///
     /// This method will automatically add `tok` to `expected_tokens` if `tok` is not
     /// encountered.
+    #[inline]
     fn check(&mut self, tok: &TokenKind) -> bool {
         let is_present = self.token == *tok;
         if !is_present {
@@ -556,6 +560,7 @@ impl<'a> Parser<'a> {
         is_present
     }
 
+    #[inline]
     fn check_noexpect(&self, tok: &TokenKind) -> bool {
         self.token == *tok
     }
@@ -564,6 +569,7 @@ impl<'a> Parser<'a> {
     ///
     /// the main purpose of this function is to reduce the cluttering of the suggestions list
     /// which using the normal eat method could introduce in some cases.
+    #[inline]
     pub fn eat_noexpect(&mut self, tok: &TokenKind) -> bool {
         let is_present = self.check_noexpect(tok);
         if is_present {
@@ -573,6 +579,7 @@ impl<'a> Parser<'a> {
     }
 
     /// Consumes a token 'tok' if it exists. Returns whether the given token was present.
+    #[inline]
     pub fn eat(&mut self, tok: &TokenKind) -> bool {
         let is_present = self.check(tok);
         if is_present {
@@ -583,11 +590,13 @@ impl<'a> Parser<'a> {
 
     /// If the next token is the given keyword, returns `true` without eating it.
     /// An expectation is also added for diagnostics purposes.
+    #[inline]
     fn check_keyword(&mut self, kw: Symbol) -> bool {
         self.expected_tokens.push(TokenType::Keyword(kw));
         self.token.is_keyword(kw)
     }
 
+    #[inline]
     fn check_keyword_case(&mut self, kw: Symbol, case: Case) -> bool {
         if self.check_keyword(kw) {
             return true;
@@ -606,6 +615,7 @@ impl<'a> Parser<'a> {
     /// If the next token is the given keyword, eats it and returns `true`.
     /// Otherwise, returns `false`. An expectation is also added for diagnostics purposes.
     // Public for rustfmt usage.
+    #[inline]
     pub fn eat_keyword(&mut self, kw: Symbol) -> bool {
         if self.check_keyword(kw) {
             self.bump();
@@ -618,6 +628,7 @@ impl<'a> Parser<'a> {
     /// Eats a keyword, optionally ignoring the case.
     /// If the case differs (and is ignored) an error is issued.
     /// This is useful for recovery.
+    #[inline]
     fn eat_keyword_case(&mut self, kw: Symbol, case: Case) -> bool {
         if self.eat_keyword(kw) {
             return true;
@@ -635,6 +646,7 @@ impl<'a> Parser<'a> {
         false
     }
 
+    #[inline]
     fn eat_keyword_noexpect(&mut self, kw: Symbol) -> bool {
         if self.token.is_keyword(kw) {
             self.bump();
@@ -656,6 +668,7 @@ impl<'a> Parser<'a> {
         self.token.is_keyword(kw) && self.look_ahead(1, |t| t.is_ident() && !t.is_reserved_ident())
     }
 
+    #[inline]
     fn check_or_expected(&mut self, ok: bool, typ: TokenType) -> bool {
         if ok {
             true
@@ -703,6 +716,7 @@ impl<'a> Parser<'a> {
 
     /// Checks to see if the next token is either `+` or `+=`.
     /// Otherwise returns `false`.
+    #[inline]
     fn check_plus(&mut self) -> bool {
         self.check_or_expected(
             self.token.is_like_plus(),
@@ -1394,7 +1408,7 @@ impl<'a> Parser<'a> {
     /// so emit a proper diagnostic.
     // Public for rustfmt usage.
     pub fn parse_visibility(&mut self, fbt: FollowedByType) -> PResult<'a, Visibility> {
-        maybe_whole!(self, NtVis, |x| x.into_inner());
+        maybe_whole!(self, NtVis, |vis| vis.into_inner());
 
         if !self.eat_keyword(kw::Pub) {
             // We need a span for our `Spanned<VisibilityKind>`, but there's inherently no
@@ -1571,8 +1585,21 @@ pub enum FlatToken {
     Empty,
 }
 
-#[derive(Debug)]
-pub enum ParseNtResult {
-    Nt(Nonterminal),
+// Metavar captures of various kinds.
+#[derive(Clone, Debug)]
+pub enum ParseNtResult<NtType> {
     Tt(TokenTree),
+    Nt(NtType),
+}
+
+impl<T> ParseNtResult<T> {
+    pub fn map_nt<F, U>(self, mut f: F) -> ParseNtResult<U>
+    where
+        F: FnMut(T) -> U,
+    {
+        match self {
+            ParseNtResult::Tt(tt) => ParseNtResult::Tt(tt),
+            ParseNtResult::Nt(nt) => ParseNtResult::Nt(f(nt)),
+        }
+    }
 }
diff --git a/compiler/rustc_parse/src/parser/nonterminal.rs b/compiler/rustc_parse/src/parser/nonterminal.rs
index f1572a18a8b..36a00df7b44 100644
--- a/compiler/rustc_parse/src/parser/nonterminal.rs
+++ b/compiler/rustc_parse/src/parser/nonterminal.rs
@@ -1,5 +1,5 @@
 use rustc_ast::ptr::P;
-use rustc_ast::token::{self, Delimiter, Nonterminal::*, NonterminalKind, Token};
+use rustc_ast::token::{self, Delimiter, Nonterminal, Nonterminal::*, NonterminalKind, Token};
 use rustc_ast::HasTokens;
 use rustc_ast_pretty::pprust;
 use rustc_errors::PResult;
@@ -66,15 +66,14 @@ impl<'a> Parser<'a> {
                 token::Interpolated(nt) => may_be_ident(&nt.0),
                 _ => false,
             },
-            NonterminalKind::PatParam { .. } | NonterminalKind::PatWithOr => {
-                match &token.kind {
+            NonterminalKind::PatParam { .. } | NonterminalKind::PatWithOr => match &token.kind {
                 token::Ident(..) |                          // box, ref, mut, and other identifiers (can stricten)
                 token::OpenDelim(Delimiter::Parenthesis) |  // tuple pattern
                 token::OpenDelim(Delimiter::Bracket) |      // slice pattern
                 token::BinOp(token::And) |                  // reference
                 token::BinOp(token::Minus) |                // negative literal
                 token::AndAnd |                             // double reference
-                token::Literal(_) |                        // literal
+                token::Literal(_) |                         // literal
                 token::DotDot |                             // range pattern (future compat)
                 token::DotDotDot |                          // range pattern (future compat)
                 token::ModSep |                             // path
@@ -84,8 +83,7 @@ impl<'a> Parser<'a> {
                 token::BinOp(token::Or) => matches!(kind, NonterminalKind::PatWithOr),
                 token::Interpolated(nt) => may_be_ident(&nt.0),
                 _ => false,
-            }
-            }
+            },
             NonterminalKind::Lifetime => match &token.kind {
                 token::Lifetime(_) => true,
                 token::Interpolated(nt) => {
@@ -102,7 +100,10 @@ impl<'a> Parser<'a> {
     /// Parse a non-terminal (e.g. MBE `:pat` or `:ident`). Inlined because there is only one call
     /// site.
     #[inline]
-    pub fn parse_nonterminal(&mut self, kind: NonterminalKind) -> PResult<'a, ParseNtResult> {
+    pub fn parse_nonterminal(
+        &mut self,
+        kind: NonterminalKind,
+    ) -> PResult<'a, ParseNtResult<Nonterminal>> {
         // A `macro_rules!` invocation may pass a captured item/expr to a proc-macro,
         // which requires having captured tokens available. Since we cannot determine
         // in advance whether or not a proc-macro will be (transitively) invoked,
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 88ae1b5420f..fbc28859535 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -435,7 +435,7 @@ impl<'a> Parser<'a> {
         syntax_loc: Option<PatternLocation>,
     ) -> PResult<'a, P<Pat>> {
         maybe_recover_from_interpolated_ty_qpath!(self, true);
-        maybe_whole!(self, NtPat, |x| x);
+        maybe_whole!(self, NtPat, |pat| pat);
 
         let mut lo = self.token.span;
 
@@ -498,11 +498,14 @@ impl<'a> Parser<'a> {
             } else {
                 PatKind::Lit(const_expr)
             }
+        } else if self.is_builtin() {
+            self.parse_pat_builtin()?
+        }
         // Don't eagerly error on semantically invalid tokens when matching
         // declarative macros, as the input to those doesn't have to be
         // semantically valid. For attribute/derive proc macros this is not the
         // case, so doing the recovery for them is fine.
-        } else if self.can_be_ident_pat()
+        else if self.can_be_ident_pat()
             || (self.is_lit_bad_ident().is_some() && self.may_recover())
         {
             // Parse `ident @ pat`
@@ -1119,6 +1122,21 @@ impl<'a> Parser<'a> {
         .contains(&self.token.kind)
     }
 
+    fn parse_pat_builtin(&mut self) -> PResult<'a, PatKind> {
+        self.parse_builtin(|self_, _lo, ident| {
+            Ok(match ident.name {
+                // builtin#deref(PAT)
+                sym::deref => Some(ast::PatKind::Deref(self_.parse_pat_allow_top_alt(
+                    None,
+                    RecoverComma::Yes,
+                    RecoverColon::Yes,
+                    CommaRecoveryMode::LikelyTuple,
+                )?)),
+                _ => None,
+            })
+        })
+    }
+
     /// Parses `box pat`
     fn parse_pat_box(&mut self) -> PResult<'a, PatKind> {
         let box_span = self.prev_token.span;
diff --git a/compiler/rustc_parse/src/parser/stmt.rs b/compiler/rustc_parse/src/parser/stmt.rs
index fc907760531..6601011665b 100644
--- a/compiler/rustc_parse/src/parser/stmt.rs
+++ b/compiler/rustc_parse/src/parser/stmt.rs
@@ -40,8 +40,8 @@ impl<'a> Parser<'a> {
         }))
     }
 
-    /// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of whether
-    /// or not we have attributes
+    /// If `force_collect` is [`ForceCollect::Yes`], forces collection of tokens regardless of
+    /// whether or not we have attributes.
     // Public for `cfg_eval` macro expansion.
     pub fn parse_stmt_without_recovery(
         &mut self,
@@ -51,18 +51,12 @@ impl<'a> Parser<'a> {
         let attrs = self.parse_outer_attributes()?;
         let lo = self.token.span;
 
-        // Don't use `maybe_whole` so that we have precise control
-        // over when we bump the parser
-        if let token::Interpolated(nt) = &self.token.kind
-            && let token::NtStmt(stmt) = &nt.0
-        {
-            let mut stmt = stmt.clone();
-            self.bump();
+        maybe_whole!(self, NtStmt, |stmt| {
             stmt.visit_attrs(|stmt_attrs| {
                 attrs.prepend_to_nt_inner(stmt_attrs);
             });
-            return Ok(Some(stmt.into_inner()));
-        }
+            Some(stmt.into_inner())
+        });
 
         if self.token.is_keyword(kw::Mut) && self.is_keyword_ahead(1, &[kw::Let]) {
             self.bump();
@@ -539,7 +533,7 @@ impl<'a> Parser<'a> {
         blk_mode: BlockCheckMode,
         can_be_struct_literal: bool,
     ) -> PResult<'a, (AttrVec, P<Block>)> {
-        maybe_whole!(self, NtBlock, |x| (AttrVec::new(), x));
+        maybe_whole!(self, NtBlock, |block| (AttrVec::new(), block));
 
         let maybe_ident = self.prev_token.clone();
         self.maybe_recover_unexpected_block_label();
@@ -643,7 +637,7 @@ impl<'a> Parser<'a> {
         recover: AttemptLocalParseRecovery,
     ) -> PResult<'a, Option<Stmt>> {
         // Skip looking for a trailing semicolon when we have an interpolated statement.
-        maybe_whole!(self, NtStmt, |x| Some(x.into_inner()));
+        maybe_whole!(self, NtStmt, |stmt| Some(stmt.into_inner()));
 
         let Some(mut stmt) = self.parse_stmt_without_recovery(true, ForceCollect::No)? else {
             return Ok(None);
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index 2385c18c089..1cea32cb90f 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -250,7 +250,7 @@ impl<'a> Parser<'a> {
     ) -> PResult<'a, P<Ty>> {
         let allow_qpath_recovery = recover_qpath == RecoverQPath::Yes;
         maybe_recover_from_interpolated_ty_qpath!(self, allow_qpath_recovery);
-        maybe_whole!(self, NtTy, |x| x);
+        maybe_whole!(self, NtTy, |ty| ty);
 
         let lo = self.token.span;
         let mut impl_dyn_multi = false;
diff --git a/compiler/rustc_passes/src/check_const.rs b/compiler/rustc_passes/src/check_const.rs
index 8080216a252..4a1a2049083 100644
--- a/compiler/rustc_passes/src/check_const.rs
+++ b/compiler/rustc_passes/src/check_const.rs
@@ -48,7 +48,7 @@ impl NonConstExpr {
             Self::Match(TryDesugar(_)) => &[sym::const_try],
 
             // All other expressions are allowed.
-            Self::Loop(Loop | While) | Self::Match(Normal | FormatArgs) => &[],
+            Self::Loop(Loop | While) | Self::Match(Normal | Postfix | FormatArgs) => &[],
         };
 
         Some(gates)
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index 350f7e166bf..c3124556648 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -831,7 +831,7 @@ fn create_and_seed_worklist(
         .collect::<Vec<_>>();
 
     let crate_items = tcx.hir_crate_items(());
-    for id in crate_items.items() {
+    for id in crate_items.free_items() {
         check_item(tcx, &mut worklist, &mut struct_constructors, &mut unsolved_impl_item, id);
     }
 
@@ -1084,7 +1084,7 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
 
     let module_items = tcx.hir_module_items(module);
 
-    for item in module_items.items() {
+    for item in module_items.free_items() {
         let def_kind = tcx.def_kind(item.owner_id);
 
         let mut dead_codes = Vec::new();
diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
index d742ffc69e4..d0dba938b3b 100644
--- a/compiler/rustc_passes/src/hir_stats.rs
+++ b/compiler/rustc_passes/src/hir_stats.rs
@@ -300,6 +300,7 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
                 Path,
                 Tuple,
                 Box,
+                Deref,
                 Ref,
                 Lit,
                 Range,
@@ -566,6 +567,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
                 Path,
                 Tuple,
                 Box,
+                Deref,
                 Ref,
                 Lit,
                 Range,
diff --git a/compiler/rustc_passes/src/reachable.rs b/compiler/rustc_passes/src/reachable.rs
index b7135de08ba..c2e604b02b3 100644
--- a/compiler/rustc_passes/src/reachable.rs
+++ b/compiler/rustc_passes/src/reachable.rs
@@ -437,7 +437,7 @@ fn reachable_set(tcx: TyCtxt<'_>, (): ()) -> LocalDefIdSet {
         // trait is a lang item.
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             check_item(tcx, id, &mut reachable_context.worklist, effective_visibilities);
         }
 
diff --git a/compiler/rustc_pattern_analysis/Cargo.toml b/compiler/rustc_pattern_analysis/Cargo.toml
index b9bdcb41929..6357d18b9da 100644
--- a/compiler/rustc_pattern_analysis/Cargo.toml
+++ b/compiler/rustc_pattern_analysis/Cargo.toml
@@ -22,6 +22,10 @@ smallvec = { version = "1.8.1", features = ["union"] }
 tracing = "0.1"
 # tidy-alphabetical-end
 
+[dev-dependencies]
+tracing-subscriber = { version = "0.3.3", default-features = false, features = ["fmt", "env-filter", "ansi"] }
+tracing-tree = "0.2.0"
+
 [features]
 default = ["rustc"]
 rustc = [
diff --git a/compiler/rustc_pattern_analysis/src/constructor.rs b/compiler/rustc_pattern_analysis/src/constructor.rs
index 5b58d7f43b2..95c5556410d 100644
--- a/compiler/rustc_pattern_analysis/src/constructor.rs
+++ b/compiler/rustc_pattern_analysis/src/constructor.rs
@@ -819,6 +819,81 @@ impl<Cx: PatCx> Constructor<Cx> {
             }
         })
     }
+
+    pub(crate) fn fmt_fields(
+        &self,
+        f: &mut fmt::Formatter<'_>,
+        ty: &Cx::Ty,
+        mut fields: impl Iterator<Item = impl fmt::Debug>,
+    ) -> fmt::Result {
+        let mut first = true;
+        let mut start_or_continue = |s| {
+            if first {
+                first = false;
+                ""
+            } else {
+                s
+            }
+        };
+        let mut start_or_comma = || start_or_continue(", ");
+
+        match self {
+            Struct | Variant(_) | UnionField => {
+                Cx::write_variant_name(f, self, ty)?;
+                // Without `cx`, we can't know which field corresponds to which, so we can't
+                // get the names of the fields. Instead we just display everything as a tuple
+                // struct, which should be good enough.
+                write!(f, "(")?;
+                for p in fields {
+                    write!(f, "{}{:?}", start_or_comma(), p)?;
+                }
+                write!(f, ")")?;
+            }
+            // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should
+            // be careful to detect strings here. However a string literal pattern will never
+            // be reported as a non-exhaustiveness witness, so we can ignore this issue.
+            Ref => {
+                write!(f, "&{:?}", &fields.next().unwrap())?;
+            }
+            Slice(slice) => {
+                write!(f, "[")?;
+                match slice.kind {
+                    SliceKind::FixedLen(_) => {
+                        for p in fields {
+                            write!(f, "{}{:?}", start_or_comma(), p)?;
+                        }
+                    }
+                    SliceKind::VarLen(prefix_len, _) => {
+                        for p in fields.by_ref().take(prefix_len) {
+                            write!(f, "{}{:?}", start_or_comma(), p)?;
+                        }
+                        write!(f, "{}..", start_or_comma())?;
+                        for p in fields {
+                            write!(f, "{}{:?}", start_or_comma(), p)?;
+                        }
+                    }
+                }
+                write!(f, "]")?;
+            }
+            Bool(b) => write!(f, "{b}")?,
+            // Best-effort, will render signed ranges incorrectly
+            IntRange(range) => write!(f, "{range:?}")?,
+            F32Range(lo, hi, end) => write!(f, "{lo}{end}{hi}")?,
+            F64Range(lo, hi, end) => write!(f, "{lo}{end}{hi}")?,
+            Str(value) => write!(f, "{value:?}")?,
+            Opaque(..) => write!(f, "<constant pattern>")?,
+            Or => {
+                for pat in fields {
+                    write!(f, "{}{:?}", start_or_continue(" | "), pat)?;
+                }
+            }
+            Never => write!(f, "!")?,
+            Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => {
+                write!(f, "_ : {:?}", ty)?
+            }
+        }
+        Ok(())
+    }
 }
 
 #[derive(Debug, Clone, Copy)]
diff --git a/compiler/rustc_pattern_analysis/src/lib.rs b/compiler/rustc_pattern_analysis/src/lib.rs
index 5c57c990323..1a1da5c55f6 100644
--- a/compiler/rustc_pattern_analysis/src/lib.rs
+++ b/compiler/rustc_pattern_analysis/src/lib.rs
@@ -49,6 +49,12 @@ pub mod index {
         }
     }
 
+    impl<V> FromIterator<V> for IdxContainer<usize, V> {
+        fn from_iter<T: IntoIterator<Item = V>>(iter: T) -> Self {
+            Self(iter.into_iter().enumerate().collect())
+        }
+    }
+
     #[derive(Debug)]
     pub struct IdxSet<T>(pub rustc_hash::FxHashSet<T>);
     impl<T: Idx> IdxSet<T> {
@@ -120,7 +126,8 @@ pub trait PatCx: Sized + fmt::Debug {
     /// `DeconstructedPat`. Only invoqued when `pat.ctor()` is `Struct | Variant(_) | UnionField`.
     fn write_variant_name(
         f: &mut fmt::Formatter<'_>,
-        pat: &crate::pat::DeconstructedPat<Self>,
+        ctor: &crate::constructor::Constructor<Self>,
+        ty: &Self::Ty,
     ) -> fmt::Result;
 
     /// Raise a bug.
diff --git a/compiler/rustc_pattern_analysis/src/pat.rs b/compiler/rustc_pattern_analysis/src/pat.rs
index e7eed673c94..5f388ee9f89 100644
--- a/compiler/rustc_pattern_analysis/src/pat.rs
+++ b/compiler/rustc_pattern_analysis/src/pat.rs
@@ -138,81 +138,11 @@ impl<Cx: PatCx> DeconstructedPat<Cx> {
 /// This is best effort and not good enough for a `Display` impl.
 impl<Cx: PatCx> fmt::Debug for DeconstructedPat<Cx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let pat = self;
-        let mut first = true;
-        let mut start_or_continue = |s| {
-            if first {
-                first = false;
-                ""
-            } else {
-                s
-            }
-        };
-        let mut start_or_comma = || start_or_continue(", ");
-
         let mut fields: Vec<_> = (0..self.arity).map(|_| PatOrWild::Wild).collect();
         for ipat in self.iter_fields() {
             fields[ipat.idx] = PatOrWild::Pat(&ipat.pat);
         }
-
-        match pat.ctor() {
-            Struct | Variant(_) | UnionField => {
-                Cx::write_variant_name(f, pat)?;
-                // Without `cx`, we can't know which field corresponds to which, so we can't
-                // get the names of the fields. Instead we just display everything as a tuple
-                // struct, which should be good enough.
-                write!(f, "(")?;
-                for p in fields {
-                    write!(f, "{}", start_or_comma())?;
-                    write!(f, "{p:?}")?;
-                }
-                write!(f, ")")
-            }
-            // Note: given the expansion of `&str` patterns done in `expand_pattern`, we should
-            // be careful to detect strings here. However a string literal pattern will never
-            // be reported as a non-exhaustiveness witness, so we can ignore this issue.
-            Ref => {
-                write!(f, "&{:?}", &fields[0])
-            }
-            Slice(slice) => {
-                write!(f, "[")?;
-                match slice.kind {
-                    SliceKind::FixedLen(_) => {
-                        for p in fields {
-                            write!(f, "{}{:?}", start_or_comma(), p)?;
-                        }
-                    }
-                    SliceKind::VarLen(prefix_len, _) => {
-                        for p in &fields[..prefix_len] {
-                            write!(f, "{}{:?}", start_or_comma(), p)?;
-                        }
-                        write!(f, "{}", start_or_comma())?;
-                        write!(f, "..")?;
-                        for p in &fields[prefix_len..] {
-                            write!(f, "{}{:?}", start_or_comma(), p)?;
-                        }
-                    }
-                }
-                write!(f, "]")
-            }
-            Bool(b) => write!(f, "{b}"),
-            // Best-effort, will render signed ranges incorrectly
-            IntRange(range) => write!(f, "{range:?}"),
-            F32Range(lo, hi, end) => write!(f, "{lo}{end}{hi}"),
-            F64Range(lo, hi, end) => write!(f, "{lo}{end}{hi}"),
-            Str(value) => write!(f, "{value:?}"),
-            Opaque(..) => write!(f, "<constant pattern>"),
-            Or => {
-                for pat in fields {
-                    write!(f, "{}{:?}", start_or_continue(" | "), pat)?;
-                }
-                Ok(())
-            }
-            Never => write!(f, "!"),
-            Wildcard | Missing | NonExhaustive | Hidden | PrivateUninhabited => {
-                write!(f, "_ : {:?}", pat.ty())
-            }
-        }
+        self.ctor().fmt_fields(f, self.ty(), fields.into_iter())
     }
 }
 
@@ -295,7 +225,6 @@ impl<'p, Cx: PatCx> fmt::Debug for PatOrWild<'p, Cx> {
 
 /// Same idea as `DeconstructedPat`, except this is a fictitious pattern built up for diagnostics
 /// purposes. As such they don't use interning and can be cloned.
-#[derive(Debug)]
 pub struct WitnessPat<Cx: PatCx> {
     ctor: Constructor<Cx>,
     pub(crate) fields: Vec<WitnessPat<Cx>>,
@@ -353,3 +282,10 @@ impl<Cx: PatCx> WitnessPat<Cx> {
         self.fields.iter()
     }
 }
+
+/// This is best effort and not good enough for a `Display` impl.
+impl<Cx: PatCx> fmt::Debug for WitnessPat<Cx> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.ctor().fmt_fields(f, self.ty(), self.fields.iter())
+    }
+}
diff --git a/compiler/rustc_pattern_analysis/src/rustc.rs b/compiler/rustc_pattern_analysis/src/rustc.rs
index eedc00a5613..ae3eabe1745 100644
--- a/compiler/rustc_pattern_analysis/src/rustc.rs
+++ b/compiler/rustc_pattern_analysis/src/rustc.rs
@@ -462,6 +462,12 @@ impl<'p, 'tcx: 'p> RustcPatCtxt<'p, 'tcx> {
                     _ => bug!("pattern has unexpected type: pat: {:?}, ty: {:?}", pat, ty),
                 };
             }
+            PatKind::DerefPattern { .. } => {
+                // FIXME(deref_patterns): At least detect that `box _` is irrefutable.
+                fields = vec![];
+                arity = 0;
+                ctor = Opaque(OpaqueId::new());
+            }
             PatKind::Leaf { subpatterns } | PatKind::Variant { subpatterns, .. } => {
                 match ty.kind() {
                     ty::Tuple(fs) => {
@@ -874,13 +880,14 @@ impl<'p, 'tcx: 'p> PatCx for RustcPatCtxt<'p, 'tcx> {
 
     fn write_variant_name(
         f: &mut fmt::Formatter<'_>,
-        pat: &crate::pat::DeconstructedPat<Self>,
+        ctor: &crate::constructor::Constructor<Self>,
+        ty: &Self::Ty,
     ) -> fmt::Result {
-        if let ty::Adt(adt, _) = pat.ty().kind() {
+        if let ty::Adt(adt, _) = ty.kind() {
             if adt.is_box() {
                 write!(f, "Box")?
             } else {
-                let variant = adt.variant(Self::variant_index_for_adt(pat.ctor(), *adt));
+                let variant = adt.variant(Self::variant_index_for_adt(ctor, *adt));
                 write!(f, "{}", variant.name)?;
             }
         }
diff --git a/compiler/rustc_pattern_analysis/src/usefulness.rs b/compiler/rustc_pattern_analysis/src/usefulness.rs
index 3760db8b688..cdc03eaeb37 100644
--- a/compiler/rustc_pattern_analysis/src/usefulness.rs
+++ b/compiler/rustc_pattern_analysis/src/usefulness.rs
@@ -1042,7 +1042,7 @@ struct MatrixRow<'p, Cx: PatCx> {
     is_under_guard: bool,
     /// When we specialize, we remember which row of the original matrix produced a given row of the
     /// specialized matrix. When we unspecialize, we use this to propagate usefulness back up the
-    /// callstack.
+    /// callstack. On creation, this stores the index of the original match arm.
     parent_row: usize,
     /// False when the matrix is just built. This is set to `true` by
     /// [`compute_exhaustiveness_and_usefulness`] if the arm is found to be useful.
@@ -1163,10 +1163,10 @@ impl<'p, Cx: PatCx> Matrix<'p, Cx> {
             place_info: smallvec![place_info],
             wildcard_row_is_relevant: true,
         };
-        for (row_id, arm) in arms.iter().enumerate() {
+        for (arm_id, arm) in arms.iter().enumerate() {
             let v = MatrixRow {
                 pats: PatStack::from_pattern(arm.pat),
-                parent_row: row_id, // dummy, we don't read it
+                parent_row: arm_id,
                 is_under_guard: arm.has_guard,
                 useful: false,
                 intersects: BitSet::new_empty(0), // Initialized in `Matrix::expand_and_push`.
@@ -1738,6 +1738,9 @@ pub struct UsefulnessReport<'p, Cx: PatCx> {
     /// If the match is exhaustive, this is empty. If not, this contains witnesses for the lack of
     /// exhaustiveness.
     pub non_exhaustiveness_witnesses: Vec<WitnessPat<Cx>>,
+    /// For each arm, a set of indices of arms above it that have non-empty intersection, i.e. there
+    /// is a value matched by both arms. This may miss real intersections.
+    pub arm_intersections: Vec<BitSet<usize>>,
 }
 
 /// Computes whether a match is exhaustive and which of its arms are useful.
@@ -1769,5 +1772,19 @@ pub fn compute_match_usefulness<'p, Cx: PatCx>(
         })
         .collect();
 
-    Ok(UsefulnessReport { arm_usefulness, non_exhaustiveness_witnesses })
+    let mut arm_intersections: Vec<_> =
+        arms.iter().enumerate().map(|(i, _)| BitSet::new_empty(i)).collect();
+    for row in matrix.rows() {
+        let arm_id = row.parent_row;
+        for intersection in row.intersects.iter() {
+            // Convert the matrix row ids into arm ids (they can differ because we expand or-patterns).
+            let arm_intersection = matrix.rows[intersection].parent_row;
+            // Note: self-intersection can happen with or-patterns.
+            if arm_intersection != arm_id {
+                arm_intersections[arm_id].insert(arm_intersection);
+            }
+        }
+    }
+
+    Ok(UsefulnessReport { arm_usefulness, non_exhaustiveness_witnesses, arm_intersections })
 }
diff --git a/compiler/rustc_pattern_analysis/tests/common/mod.rs b/compiler/rustc_pattern_analysis/tests/common/mod.rs
new file mode 100644
index 00000000000..e72fddb9e9a
--- /dev/null
+++ b/compiler/rustc_pattern_analysis/tests/common/mod.rs
@@ -0,0 +1,315 @@
+use rustc_pattern_analysis::{
+    constructor::{
+        Constructor, ConstructorSet, IntRange, MaybeInfiniteInt, RangeEnd, VariantVisibility,
+    },
+    usefulness::{PlaceValidity, UsefulnessReport},
+    Captures, MatchArm, PatCx, PrivateUninhabitedField,
+};
+
+/// Sets up `tracing` for easier debugging. Tries to look like the `rustc` setup.
+pub fn init_tracing() {
+    use tracing_subscriber::layer::SubscriberExt;
+    use tracing_subscriber::util::SubscriberInitExt;
+    use tracing_subscriber::Layer;
+    let _ = tracing_tree::HierarchicalLayer::default()
+        .with_writer(std::io::stderr)
+        .with_indent_lines(true)
+        .with_ansi(true)
+        .with_targets(true)
+        .with_indent_amount(2)
+        .with_subscriber(
+            tracing_subscriber::Registry::default()
+                .with(tracing_subscriber::EnvFilter::from_default_env()),
+        )
+        .try_init();
+}
+
+/// A simple set of types.
+#[allow(dead_code)]
+#[derive(Debug, Copy, Clone)]
+pub enum Ty {
+    /// Booleans
+    Bool,
+    /// 8-bit unsigned integers
+    U8,
+    /// Tuples.
+    Tuple(&'static [Ty]),
+    /// A struct with `arity` fields of type `ty`.
+    BigStruct { arity: usize, ty: &'static Ty },
+    /// A enum with `arity` variants of type `ty`.
+    BigEnum { arity: usize, ty: &'static Ty },
+}
+
+/// The important logic.
+impl Ty {
+    pub fn sub_tys(&self, ctor: &Constructor<Cx>) -> Vec<Self> {
+        use Constructor::*;
+        match (ctor, *self) {
+            (Struct, Ty::Tuple(tys)) => tys.iter().copied().collect(),
+            (Struct, Ty::BigStruct { arity, ty }) => (0..arity).map(|_| *ty).collect(),
+            (Variant(_), Ty::BigEnum { ty, .. }) => vec![*ty],
+            (Bool(..) | IntRange(..) | NonExhaustive | Missing | Wildcard, _) => vec![],
+            _ => panic!("Unexpected ctor {ctor:?} for type {self:?}"),
+        }
+    }
+
+    pub fn ctor_set(&self) -> ConstructorSet<Cx> {
+        match *self {
+            Ty::Bool => ConstructorSet::Bool,
+            Ty::U8 => ConstructorSet::Integers {
+                range_1: IntRange::from_range(
+                    MaybeInfiniteInt::new_finite_uint(0),
+                    MaybeInfiniteInt::new_finite_uint(255),
+                    RangeEnd::Included,
+                ),
+                range_2: None,
+            },
+            Ty::Tuple(..) | Ty::BigStruct { .. } => ConstructorSet::Struct { empty: false },
+            Ty::BigEnum { arity, .. } => ConstructorSet::Variants {
+                variants: (0..arity).map(|_| VariantVisibility::Visible).collect(),
+                non_exhaustive: false,
+            },
+        }
+    }
+
+    pub fn write_variant_name(
+        &self,
+        f: &mut std::fmt::Formatter<'_>,
+        ctor: &Constructor<Cx>,
+    ) -> std::fmt::Result {
+        match (*self, ctor) {
+            (Ty::Tuple(..), _) => Ok(()),
+            (Ty::BigStruct { .. }, _) => write!(f, "BigStruct"),
+            (Ty::BigEnum { .. }, Constructor::Variant(i)) => write!(f, "BigEnum::Variant{i}"),
+            _ => write!(f, "{:?}::{:?}", self, ctor),
+        }
+    }
+}
+
+/// Compute usefulness in our simple context (and set up tracing for easier debugging).
+pub fn compute_match_usefulness<'p>(
+    arms: &[MatchArm<'p, Cx>],
+    ty: Ty,
+    scrut_validity: PlaceValidity,
+    complexity_limit: Option<usize>,
+) -> Result<UsefulnessReport<'p, Cx>, ()> {
+    init_tracing();
+    rustc_pattern_analysis::usefulness::compute_match_usefulness(
+        &Cx,
+        arms,
+        ty,
+        scrut_validity,
+        complexity_limit,
+    )
+}
+
+#[derive(Debug)]
+pub struct Cx;
+
+/// The context for pattern analysis. Forwards anything interesting to `Ty` methods.
+impl PatCx for Cx {
+    type Ty = Ty;
+    type Error = ();
+    type VariantIdx = usize;
+    type StrLit = ();
+    type ArmData = ();
+    type PatData = ();
+
+    fn is_exhaustive_patterns_feature_on(&self) -> bool {
+        false
+    }
+
+    fn is_min_exhaustive_patterns_feature_on(&self) -> bool {
+        false
+    }
+
+    fn ctor_arity(&self, ctor: &Constructor<Self>, ty: &Self::Ty) -> usize {
+        ty.sub_tys(ctor).len()
+    }
+
+    fn ctor_sub_tys<'a>(
+        &'a self,
+        ctor: &'a Constructor<Self>,
+        ty: &'a Self::Ty,
+    ) -> impl Iterator<Item = (Self::Ty, PrivateUninhabitedField)> + ExactSizeIterator + Captures<'a>
+    {
+        ty.sub_tys(ctor).into_iter().map(|ty| (ty, PrivateUninhabitedField(false)))
+    }
+
+    fn ctors_for_ty(&self, ty: &Self::Ty) -> Result<ConstructorSet<Self>, Self::Error> {
+        Ok(ty.ctor_set())
+    }
+
+    fn write_variant_name(
+        f: &mut std::fmt::Formatter<'_>,
+        ctor: &Constructor<Self>,
+        ty: &Self::Ty,
+    ) -> std::fmt::Result {
+        ty.write_variant_name(f, ctor)
+    }
+
+    fn bug(&self, fmt: std::fmt::Arguments<'_>) -> Self::Error {
+        panic!("{}", fmt)
+    }
+
+    /// Abort when reaching the complexity limit. This is what we'll check in tests.
+    fn complexity_exceeded(&self) -> Result<(), Self::Error> {
+        Err(())
+    }
+}
+
+/// Construct a single pattern; see `pats!()`.
+#[allow(unused_macros)]
+macro_rules! pat {
+    ($($rest:tt)*) => {{
+        let mut vec = pats!($($rest)*);
+        vec.pop().unwrap()
+    }};
+}
+
+/// A macro to construct patterns. Called like `pats!(type_expr; pattern, pattern, ..)` and returns
+/// a `Vec<DeconstructedPat>`. A pattern can be nested and looks like `Constructor(pat, pat)` or
+/// `Constructor { .i: pat, .j: pat }`, where `Constructor` is `Struct`, `Variant.i` (with index
+/// `i`), as well as booleans and integer ranges.
+///
+/// The general structure of the macro is a tt-muncher with several stages identified with
+/// `@something(args)`. The args are a key-value list (the keys ensure we don't mix the arguments
+/// around) which is passed down and modified as needed. We then parse token-trees from
+/// left-to-right. Non-trivial recursion happens when we parse the arguments to a pattern: we
+/// recurse to parse the tokens inside `{..}`/`(..)`, and then we continue parsing anything that
+/// follows.
+macro_rules! pats {
+    // Entrypoint
+    // Parse `type; ..`
+    ($ty:expr; $($rest:tt)*) => {{
+        #[allow(unused_imports)]
+        use rustc_pattern_analysis::{
+            constructor::{Constructor, IntRange, MaybeInfiniteInt, RangeEnd},
+            pat::DeconstructedPat,
+        };
+        let ty = $ty;
+        // The heart of the macro is designed to push `IndexedPat`s into a `Vec`, so we work around
+        // that.
+        let sub_tys = ::std::iter::repeat(&ty);
+        let mut vec = Vec::new();
+        pats!(@ctor(vec:vec, sub_tys:sub_tys, idx:0) $($rest)*);
+        vec.into_iter().map(|ipat| ipat.pat).collect::<Vec<_>>()
+    }};
+
+    // Parse `constructor ..`
+
+    (@ctor($($args:tt)*) true $($rest:tt)*) => {{
+        let ctor = Constructor::Bool(true);
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) false $($rest:tt)*) => {{
+        let ctor = Constructor::Bool(false);
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) Struct $($rest:tt)*) => {{
+        let ctor = Constructor::Struct;
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) ( $($fields:tt)* ) $($rest:tt)*) => {{
+        let ctor = Constructor::Struct; // tuples
+        pats!(@pat($($args)*, ctor:ctor) ( $($fields)* ) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) Variant.$variant:ident $($rest:tt)*) => {{
+        let ctor = Constructor::Variant($variant);
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) Variant.$variant:literal $($rest:tt)*) => {{
+        let ctor = Constructor::Variant($variant);
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) _ $($rest:tt)*) => {{
+        let ctor = Constructor::Wildcard;
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+
+    // Integers and int ranges
+    (@ctor($($args:tt)*) $($start:literal)?..$end:literal $($rest:tt)*) => {{
+        let ctor = Constructor::IntRange(IntRange::from_range(
+            pats!(@rangeboundary- $($start)?),
+            pats!(@rangeboundary+ $end),
+            RangeEnd::Excluded,
+        ));
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) $($start:literal)?.. $($rest:tt)*) => {{
+        let ctor = Constructor::IntRange(IntRange::from_range(
+            pats!(@rangeboundary- $($start)?),
+            pats!(@rangeboundary+),
+            RangeEnd::Excluded,
+        ));
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) $($start:literal)?..=$end:literal $($rest:tt)*) => {{
+        let ctor = Constructor::IntRange(IntRange::from_range(
+            pats!(@rangeboundary- $($start)?),
+            pats!(@rangeboundary+ $end),
+            RangeEnd::Included,
+        ));
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    (@ctor($($args:tt)*) $int:literal $($rest:tt)*) => {{
+        let ctor = Constructor::IntRange(IntRange::from_range(
+            pats!(@rangeboundary- $int),
+            pats!(@rangeboundary+ $int),
+            RangeEnd::Included,
+        ));
+        pats!(@pat($($args)*, ctor:ctor) $($rest)*)
+    }};
+    // Utility to manage range boundaries.
+    (@rangeboundary $sign:tt $int:literal) => { MaybeInfiniteInt::new_finite_uint($int) };
+    (@rangeboundary -) => { MaybeInfiniteInt::NegInfinity };
+    (@rangeboundary +) => { MaybeInfiniteInt::PosInfinity };
+
+    // Parse subfields: `(..)` or `{..}`
+
+    // Constructor with no fields, e.g. `bool` or `Variant.1`.
+    (@pat($($args:tt)*) $(,)?) => {
+        pats!(@pat($($args)*) {})
+    };
+    (@pat($($args:tt)*) , $($rest:tt)*) => {
+        pats!(@pat($($args)*) {}, $($rest)*)
+    };
+    // `(..)` and `{..}` are treated the same.
+    (@pat($($args:tt)*) ( $($subpat:tt)* ) $($rest:tt)*) => {{
+        pats!(@pat($($args)*) { $($subpat)* } $($rest)*)
+    }};
+    (@pat(vec:$vec:expr, sub_tys:$sub_tys:expr, idx:$idx:expr, ctor:$ctor:expr) { $($fields:tt)* } $($rest:tt)*) => {{
+        let sub_tys = $sub_tys;
+        let index = $idx;
+        // Silly dance to work with both a vec and `iter::repeat()`.
+        let ty = *(&sub_tys).clone().into_iter().nth(index).unwrap();
+        let ctor = $ctor;
+        let ctor_sub_tys = &ty.sub_tys(&ctor);
+        #[allow(unused_mut)]
+        let mut fields = Vec::new();
+        // Parse subpatterns (note the leading comma).
+        pats!(@fields(idx:0, vec:fields, sub_tys:ctor_sub_tys) ,$($fields)*);
+        let arity = ctor_sub_tys.len();
+        let pat = DeconstructedPat::new(ctor, fields, arity, ty, ()).at_index(index);
+        $vec.push(pat);
+
+        // Continue parsing further patterns.
+        pats!(@fields(idx:index+1, vec:$vec, sub_tys:sub_tys) $($rest)*);
+    }};
+
+    // Parse fields one by one.
+
+    // No fields left.
+    (@fields($($args:tt)*) $(,)?) => {};
+    // `.i: pat` sets the current index to `i`.
+    (@fields(idx:$_idx:expr, $($args:tt)*) , .$idx:literal : $($rest:tt)*) => {{
+        pats!(@ctor($($args)*, idx:$idx) $($rest)*);
+    }};
+    (@fields(idx:$_idx:expr, $($args:tt)*) , .$idx:ident : $($rest:tt)*) => {{
+        pats!(@ctor($($args)*, idx:$idx) $($rest)*);
+    }};
+    // Field without an explicit index; we use the current index which gets incremented above.
+    (@fields(idx:$idx:expr, $($args:tt)*) , $($rest:tt)*) => {{
+        pats!(@ctor($($args)*, idx:$idx) $($rest)*);
+    }};
+}
diff --git a/compiler/rustc_pattern_analysis/tests/complexity.rs b/compiler/rustc_pattern_analysis/tests/complexity.rs
new file mode 100644
index 00000000000..93f455c6257
--- /dev/null
+++ b/compiler/rustc_pattern_analysis/tests/complexity.rs
@@ -0,0 +1,109 @@
+//! Test the pattern complexity limit.
+use common::*;
+use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm};
+
+#[macro_use]
+mod common;
+
+/// Analyze a match made of these patterns. Ignore the report; we only care whether we exceeded the
+/// limit or not.
+fn check(patterns: &[DeconstructedPat<Cx>], complexity_limit: usize) -> Result<(), ()> {
+    let ty = *patterns[0].ty();
+    let arms: Vec<_> =
+        patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect();
+    compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, Some(complexity_limit))
+        .map(|_report| ())
+}
+
+/// Asserts that analyzing this match takes exactly `complexity` steps.
+#[track_caller]
+fn assert_complexity(patterns: Vec<DeconstructedPat<Cx>>, complexity: usize) {
+    assert!(check(&patterns, complexity).is_ok());
+    assert!(check(&patterns, complexity - 1).is_err());
+}
+
+/// Construct a match like:
+/// ```ignore(illustrative)
+/// match ... {
+///     BigStruct { field01: true, .. } => {}
+///     BigStruct { field02: true, .. } => {}
+///     BigStruct { field03: true, .. } => {}
+///     BigStruct { field04: true, .. } => {}
+///     ...
+///     _ => {}
+/// }
+/// ```
+fn diagonal_match(arity: usize) -> Vec<DeconstructedPat<Cx>> {
+    let struct_ty = Ty::BigStruct { arity, ty: &Ty::Bool };
+    let mut patterns = vec![];
+    for i in 0..arity {
+        patterns.push(pat!(struct_ty; Struct { .i: true }));
+    }
+    patterns.push(pat!(struct_ty; _));
+    patterns
+}
+
+/// Construct a match like:
+/// ```ignore(illustrative)
+/// match ... {
+///     BigStruct { field01: true, .. } => {}
+///     BigStruct { field02: true, .. } => {}
+///     BigStruct { field03: true, .. } => {}
+///     BigStruct { field04: true, .. } => {}
+///     ...
+///     BigStruct { field01: false, .. } => {}
+///     BigStruct { field02: false, .. } => {}
+///     BigStruct { field03: false, .. } => {}
+///     BigStruct { field04: false, .. } => {}
+///     ...
+///     _ => {}
+/// }
+/// ```
+fn diagonal_exponential_match(arity: usize) -> Vec<DeconstructedPat<Cx>> {
+    let struct_ty = Ty::BigStruct { arity, ty: &Ty::Bool };
+    let mut patterns = vec![];
+    for i in 0..arity {
+        patterns.push(pat!(struct_ty; Struct { .i: true }));
+    }
+    for i in 0..arity {
+        patterns.push(pat!(struct_ty; Struct { .i: false }));
+    }
+    patterns.push(pat!(struct_ty; _));
+    patterns
+}
+
+#[test]
+fn test_diagonal_struct_match() {
+    // These cases are nicely linear: we check `arity` patterns with exactly one `true`, matching
+    // in 2 branches each, and a final pattern with all `false`, matching only the `_` branch.
+    assert_complexity(diagonal_match(20), 41);
+    assert_complexity(diagonal_match(30), 61);
+    // This case goes exponential.
+    assert!(check(&diagonal_exponential_match(10), 10000).is_err());
+}
+
+/// Construct a match like:
+/// ```ignore(illustrative)
+/// match ... {
+///     BigEnum::Variant1(_) => {}
+///     BigEnum::Variant2(_) => {}
+///     BigEnum::Variant3(_) => {}
+///     ...
+///     _ => {}
+/// }
+/// ```
+fn big_enum(arity: usize) -> Vec<DeconstructedPat<Cx>> {
+    let enum_ty = Ty::BigEnum { arity, ty: &Ty::Bool };
+    let mut patterns = vec![];
+    for i in 0..arity {
+        patterns.push(pat!(enum_ty; Variant.i));
+    }
+    patterns.push(pat!(enum_ty; _));
+    patterns
+}
+
+#[test]
+fn test_big_enum() {
+    // We try 2 branches per variant.
+    assert_complexity(big_enum(20), 40);
+}
diff --git a/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs b/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs
new file mode 100644
index 00000000000..4c6c72fa8ec
--- /dev/null
+++ b/compiler/rustc_pattern_analysis/tests/exhaustiveness.rs
@@ -0,0 +1,77 @@
+//! Test exhaustiveness checking.
+use common::*;
+use rustc_pattern_analysis::{
+    pat::{DeconstructedPat, WitnessPat},
+    usefulness::PlaceValidity,
+    MatchArm,
+};
+
+#[macro_use]
+mod common;
+
+/// Analyze a match made of these patterns.
+fn check(patterns: Vec<DeconstructedPat<Cx>>) -> Vec<WitnessPat<Cx>> {
+    let ty = *patterns[0].ty();
+    let arms: Vec<_> =
+        patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect();
+    let report =
+        compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, None).unwrap();
+    report.non_exhaustiveness_witnesses
+}
+
+#[track_caller]
+fn assert_exhaustive(patterns: Vec<DeconstructedPat<Cx>>) {
+    let witnesses = check(patterns);
+    if !witnesses.is_empty() {
+        panic!("non-exaustive match: missing {witnesses:?}");
+    }
+}
+
+#[track_caller]
+fn assert_non_exhaustive(patterns: Vec<DeconstructedPat<Cx>>) {
+    let witnesses = check(patterns);
+    assert!(!witnesses.is_empty())
+}
+
+#[test]
+fn test_int_ranges() {
+    let ty = Ty::U8;
+    assert_exhaustive(pats!(ty;
+        0..=255,
+    ));
+    assert_exhaustive(pats!(ty;
+        0..,
+    ));
+    assert_non_exhaustive(pats!(ty;
+        0..255,
+    ));
+    assert_exhaustive(pats!(ty;
+        0..255,
+        255,
+    ));
+    assert_exhaustive(pats!(ty;
+        ..10,
+        10..
+    ));
+}
+
+#[test]
+fn test_nested() {
+    let ty = Ty::BigStruct { arity: 2, ty: &Ty::BigEnum { arity: 2, ty: &Ty::Bool } };
+    assert_non_exhaustive(pats!(ty;
+        Struct(Variant.0, _),
+    ));
+    assert_exhaustive(pats!(ty;
+        Struct(Variant.0, _),
+        Struct(Variant.1, _),
+    ));
+    assert_non_exhaustive(pats!(ty;
+        Struct(Variant.0, _),
+        Struct(_, Variant.0),
+    ));
+    assert_exhaustive(pats!(ty;
+        Struct(Variant.0, _),
+        Struct(_, Variant.0),
+        Struct(Variant.1, Variant.1),
+    ));
+}
diff --git a/compiler/rustc_pattern_analysis/tests/intersection.rs b/compiler/rustc_pattern_analysis/tests/intersection.rs
new file mode 100644
index 00000000000..4d8a21506d7
--- /dev/null
+++ b/compiler/rustc_pattern_analysis/tests/intersection.rs
@@ -0,0 +1,69 @@
+//! Test the computation of arm intersections.
+use common::*;
+use rustc_pattern_analysis::{pat::DeconstructedPat, usefulness::PlaceValidity, MatchArm};
+
+#[macro_use]
+mod common;
+
+/// Analyze a match made of these patterns and returns the computed arm intersections.
+fn check(patterns: Vec<DeconstructedPat<Cx>>) -> Vec<Vec<usize>> {
+    let ty = *patterns[0].ty();
+    let arms: Vec<_> =
+        patterns.iter().map(|pat| MatchArm { pat, has_guard: false, arm_data: () }).collect();
+    let report =
+        compute_match_usefulness(arms.as_slice(), ty, PlaceValidity::ValidOnly, None).unwrap();
+    report.arm_intersections.into_iter().map(|bitset| bitset.iter().collect()).collect()
+}
+
+#[track_caller]
+fn assert_intersects(patterns: Vec<DeconstructedPat<Cx>>, intersects: &[&[usize]]) {
+    let computed_intersects = check(patterns);
+    assert_eq!(computed_intersects, intersects);
+}
+
+#[test]
+fn test_int_ranges() {
+    let ty = Ty::U8;
+    assert_intersects(
+        pats!(ty;
+            0..=100,
+            100..,
+        ),
+        &[&[], &[0]],
+    );
+    assert_intersects(
+        pats!(ty;
+            0..=101,
+            100..,
+        ),
+        &[&[], &[0]],
+    );
+    assert_intersects(
+        pats!(ty;
+            0..100,
+            100..,
+        ),
+        &[&[], &[]],
+    );
+}
+
+#[test]
+fn test_nested() {
+    let ty = Ty::Tuple(&[Ty::Bool; 2]);
+    assert_intersects(
+        pats!(ty;
+            (true, true),
+            (true, _),
+            (_, true),
+        ),
+        &[&[], &[0], &[0, 1]],
+    );
+    // Here we shortcut because `(true, true)` is irrelevant, so we fail to detect the intersection.
+    assert_intersects(
+        pats!(ty;
+            (true, _),
+            (_, true),
+        ),
+        &[&[], &[]],
+    );
+}
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 073982ca5c3..c73fdd59609 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -1696,7 +1696,7 @@ fn check_mod_privacy(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) {
         }
     }
 
-    for id in module.items() {
+    for id in module.free_items() {
         if let ItemKind::Impl(i) = tcx.hir().item(id).kind {
             if let Some(item) = i.of_trait {
                 let trait_ref = tcx.impl_trait_ref(id.owner_id.def_id).unwrap();
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index c661be3587e..b2b339d2521 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -22,7 +22,7 @@ use rustc_errors::{
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, DefKind, LifetimeRes, NonMacroAttrKind, PartialRes, PerNS};
 use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID, LOCAL_CRATE};
-use rustc_hir::{PrimTy, TraitCandidate};
+use rustc_hir::{MissingLifetimeKind, PrimTy, TraitCandidate};
 use rustc_middle::middle::resolve_bound_vars::Set1;
 use rustc_middle::{bug, span_bug};
 use rustc_session::config::{CrateType, ResolveDocLinks};
@@ -44,9 +44,7 @@ type Res = def::Res<NodeId>;
 
 type IdentMap<T> = FxHashMap<Ident, T>;
 
-use diagnostics::{
-    ElisionFnParameter, LifetimeElisionCandidate, MissingLifetime, MissingLifetimeKind,
-};
+use diagnostics::{ElisionFnParameter, LifetimeElisionCandidate, MissingLifetime};
 
 #[derive(Copy, Clone, Debug)]
 struct BindingInfo {
@@ -1637,22 +1635,16 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
     fn resolve_anonymous_lifetime(&mut self, lifetime: &Lifetime, elided: bool) {
         debug_assert_eq!(lifetime.ident.name, kw::UnderscoreLifetime);
 
-        let missing_lifetime = MissingLifetime {
-            id: lifetime.id,
-            span: lifetime.ident.span,
-            kind: if elided {
-                MissingLifetimeKind::Ampersand
-            } else {
-                MissingLifetimeKind::Underscore
-            },
-            count: 1,
-        };
+        let kind =
+            if elided { MissingLifetimeKind::Ampersand } else { MissingLifetimeKind::Underscore };
+        let missing_lifetime =
+            MissingLifetime { id: lifetime.id, span: lifetime.ident.span, kind, count: 1 };
         let elision_candidate = LifetimeElisionCandidate::Missing(missing_lifetime);
         for (i, rib) in self.lifetime_ribs.iter().enumerate().rev() {
             debug!(?rib.kind);
             match rib.kind {
                 LifetimeRibKind::AnonymousCreateParameter { binder, .. } => {
-                    let res = self.create_fresh_lifetime(lifetime.ident, binder);
+                    let res = self.create_fresh_lifetime(lifetime.ident, binder, kind);
                     self.record_lifetime_res(lifetime.id, res, elision_candidate);
                     return;
                 }
@@ -1744,13 +1736,18 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
     }
 
     #[instrument(level = "debug", skip(self))]
-    fn create_fresh_lifetime(&mut self, ident: Ident, binder: NodeId) -> LifetimeRes {
+    fn create_fresh_lifetime(
+        &mut self,
+        ident: Ident,
+        binder: NodeId,
+        kind: MissingLifetimeKind,
+    ) -> LifetimeRes {
         debug_assert_eq!(ident.name, kw::UnderscoreLifetime);
         debug!(?ident.span);
 
         // Leave the responsibility to create the `LocalDefId` to lowering.
         let param = self.r.next_node_id();
-        let res = LifetimeRes::Fresh { param, binder };
+        let res = LifetimeRes::Fresh { param, binder, kind };
         self.record_lifetime_param(param, res);
 
         // Record the created lifetime parameter so lowering can pick it up and add it to HIR.
@@ -1844,14 +1841,15 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             };
             let ident = Ident::new(kw::UnderscoreLifetime, elided_lifetime_span);
 
+            let kind = if segment.has_generic_args {
+                MissingLifetimeKind::Comma
+            } else {
+                MissingLifetimeKind::Brackets
+            };
             let missing_lifetime = MissingLifetime {
                 id: node_ids.start,
                 span: elided_lifetime_span,
-                kind: if segment.has_generic_args {
-                    MissingLifetimeKind::Comma
-                } else {
-                    MissingLifetimeKind::Brackets
-                },
+                kind,
                 count: expected_lifetimes,
             };
             let mut should_lint = true;
@@ -1897,7 +1895,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                         // Group all suggestions into the first record.
                         let mut candidate = LifetimeElisionCandidate::Missing(missing_lifetime);
                         for id in node_ids {
-                            let res = self.create_fresh_lifetime(ident, binder);
+                            let res = self.create_fresh_lifetime(ident, binder, kind);
                             self.record_lifetime_res(
                                 id,
                                 res,
@@ -4672,7 +4670,9 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
             return;
         }
 
-        if path.iter().any(|seg| seg.ident.span.from_expansion()) {
+        if finalize.path_span.from_expansion()
+            || path.iter().any(|seg| seg.ident.span.from_expansion())
+        {
             return;
         }
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 47f8cc56139..bb4294fbcfb 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -24,7 +24,7 @@ use rustc_errors::{
 use rustc_hir as hir;
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind};
 use rustc_hir::def_id::{DefId, CRATE_DEF_ID};
-use rustc_hir::PrimTy;
+use rustc_hir::{MissingLifetimeKind, PrimTy};
 use rustc_session::lint;
 use rustc_session::Session;
 use rustc_span::edit_distance::find_best_match_for_name;
@@ -109,18 +109,6 @@ pub(super) struct MissingLifetime {
     pub count: usize,
 }
 
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
-pub(super) enum MissingLifetimeKind {
-    /// An explicit `'_`.
-    Underscore,
-    /// An elided lifetime `&' ty`.
-    Ampersand,
-    /// An elided lifetime in brackets with written brackets.
-    Comma,
-    /// An elided lifetime with elided brackets.
-    Brackets,
-}
-
 /// Description of the lifetimes appearing in a function parameter.
 /// This is used to provide a literal explanation to the elision failure.
 #[derive(Clone, Debug)]
@@ -1604,18 +1592,23 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
 
         match (res, source) {
             (
-                Res::Def(DefKind::Macro(MacroKind::Bang), _),
+                Res::Def(DefKind::Macro(MacroKind::Bang), def_id),
                 PathSource::Expr(Some(Expr {
                     kind: ExprKind::Index(..) | ExprKind::Call(..), ..
                 }))
                 | PathSource::Struct,
             ) => {
+                // Don't suggest macro if it's unstable.
+                let suggestable = def_id.is_local()
+                    || self.r.tcx.lookup_stability(def_id).map_or(true, |s| s.is_stable());
+
                 err.span_label(span, fallback_label.to_string());
 
                 // Don't suggest `!` for a macro invocation if there are generic args
                 if path
                     .last()
                     .is_some_and(|segment| !segment.has_generic_args && !segment.has_lifetime_args)
+                    && suggestable
                 {
                     err.span_suggestion_verbose(
                         span.shrink_to_hi(),
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index e6eb1a3e83c..a88ae268e27 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -22,7 +22,7 @@ use rustc_span::{FileName, FileNameDisplayPreference, RealFileName, SourceFileHa
 use rustc_target::abi::Align;
 use rustc_target::spec::LinkSelfContainedComponents;
 use rustc_target::spec::{PanicStrategy, RelocModel, SanitizerSet, SplitDebuginfo};
-use rustc_target::spec::{Target, TargetTriple, TargetWarnings, TARGETS};
+use rustc_target::spec::{Target, TargetTriple, TARGETS};
 use std::collections::btree_map::{
     Iter as BTreeMapIter, Keys as BTreeMapKeysIter, Values as BTreeMapValuesIter,
 };
@@ -1549,34 +1549,25 @@ pub fn build_configuration(sess: &Session, mut user_cfg: Cfg) -> Cfg {
     user_cfg
 }
 
-pub fn build_target_config(
-    early_dcx: &EarlyDiagCtxt,
-    opts: &Options,
-    target_override: Option<Target>,
-    sysroot: &Path,
-) -> Target {
-    let target_result = target_override.map_or_else(
-        || Target::search(&opts.target_triple, sysroot),
-        |t| Ok((t, TargetWarnings::empty())),
-    );
-    let (target, target_warnings) = target_result.unwrap_or_else(|e| {
-        early_dcx.early_fatal(format!(
+pub fn build_target_config(early_dcx: &EarlyDiagCtxt, opts: &Options, sysroot: &Path) -> Target {
+    match Target::search(&opts.target_triple, sysroot) {
+        Ok((target, warnings)) => {
+            for warning in warnings.warning_messages() {
+                early_dcx.early_warn(warning)
+            }
+            if !matches!(target.pointer_width, 16 | 32 | 64) {
+                early_dcx.early_fatal(format!(
+                    "target specification was invalid: unrecognized target-pointer-width {}",
+                    target.pointer_width
+                ))
+            }
+            target
+        }
+        Err(e) => early_dcx.early_fatal(format!(
             "Error loading target specification: {e}. \
-                 Run `rustc --print target-list` for a list of built-in targets"
-        ))
-    });
-    for warning in target_warnings.warning_messages() {
-        early_dcx.early_warn(warning)
-    }
-
-    if !matches!(target.pointer_width, 16 | 32 | 64) {
-        early_dcx.early_fatal(format!(
-            "target specification was invalid: unrecognized target-pointer-width {}",
-            target.pointer_width
-        ))
+                     Run `rustc --print target-list` for a list of built-in targets"
+        )),
     }
-
-    target
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 9c94fd7027f..e6d82d6fab3 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -1008,7 +1008,7 @@ pub fn build_session(
     fluent_resources: Vec<&'static str>,
     driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
     file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
-    target_cfg: Target,
+    target: Target,
     sysroot: PathBuf,
     cfg_version: &'static str,
     ice_file: Option<PathBuf>,
@@ -1036,7 +1036,7 @@ pub fn build_session(
 
     let loader = file_loader.unwrap_or_else(|| Box::new(RealFileLoader));
     let hash_kind = sopts.unstable_opts.src_hash_algorithm.unwrap_or_else(|| {
-        if target_cfg.is_like_msvc {
+        if target.is_like_msvc {
             SourceFileHashAlgorithm::Sha256
         } else {
             SourceFileHashAlgorithm::Md5
@@ -1117,11 +1117,10 @@ pub fn build_session(
         _ => CtfeBacktrace::Disabled,
     });
 
-    let asm_arch =
-        if target_cfg.allow_asm { InlineAsmArch::from_str(&target_cfg.arch).ok() } else { None };
+    let asm_arch = if target.allow_asm { InlineAsmArch::from_str(&target.arch).ok() } else { None };
 
     let sess = Session {
-        target: target_cfg,
+        target,
         host,
         opts: sopts,
         host_tlib_path,
diff --git a/compiler/rustc_smir/src/rustc_internal/internal.rs b/compiler/rustc_smir/src/rustc_internal/internal.rs
index 2cc9bc31873..bf7346be31f 100644
--- a/compiler/rustc_smir/src/rustc_internal/internal.rs
+++ b/compiler/rustc_smir/src/rustc_internal/internal.rs
@@ -10,7 +10,7 @@ use rustc_span::Symbol;
 use stable_mir::abi::Layout;
 use stable_mir::mir::alloc::AllocId;
 use stable_mir::mir::mono::{Instance, MonoItem, StaticDef};
-use stable_mir::mir::{Mutability, Safety};
+use stable_mir::mir::{Mutability, Place, ProjectionElem, Safety};
 use stable_mir::ty::{
     Abi, AdtDef, Binder, BoundRegionKind, BoundTyKind, BoundVariableKind, ClosureKind, Const,
     DynKind, ExistentialPredicate, ExistentialProjection, ExistentialTraitRef, FloatTy, FnSig,
@@ -492,6 +492,50 @@ impl RustcInternal for Layout {
     }
 }
 
+impl RustcInternal for Place {
+    type T<'tcx> = rustc_middle::mir::Place<'tcx>;
+
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
+        rustc_middle::mir::Place {
+            local: rustc_middle::mir::Local::from_usize(self.local),
+            projection: tcx.mk_place_elems(&self.projection.internal(tables, tcx)),
+        }
+    }
+}
+
+impl RustcInternal for ProjectionElem {
+    type T<'tcx> = rustc_middle::mir::PlaceElem<'tcx>;
+
+    fn internal<'tcx>(&self, tables: &mut Tables<'_>, tcx: TyCtxt<'tcx>) -> Self::T<'tcx> {
+        match self {
+            ProjectionElem::Deref => rustc_middle::mir::PlaceElem::Deref,
+            ProjectionElem::Field(idx, ty) => {
+                rustc_middle::mir::PlaceElem::Field((*idx).into(), ty.internal(tables, tcx))
+            }
+            ProjectionElem::Index(idx) => rustc_middle::mir::PlaceElem::Index((*idx).into()),
+            ProjectionElem::ConstantIndex { offset, min_length, from_end } => {
+                rustc_middle::mir::PlaceElem::ConstantIndex {
+                    offset: *offset,
+                    min_length: *min_length,
+                    from_end: *from_end,
+                }
+            }
+            ProjectionElem::Subslice { from, to, from_end } => {
+                rustc_middle::mir::PlaceElem::Subslice { from: *from, to: *to, from_end: *from_end }
+            }
+            ProjectionElem::Downcast(idx) => {
+                rustc_middle::mir::PlaceElem::Downcast(None, idx.internal(tables, tcx))
+            }
+            ProjectionElem::OpaqueCast(ty) => {
+                rustc_middle::mir::PlaceElem::OpaqueCast(ty.internal(tables, tcx))
+            }
+            ProjectionElem::Subtype(ty) => {
+                rustc_middle::mir::PlaceElem::Subtype(ty.internal(tables, tcx))
+            }
+        }
+    }
+}
+
 impl<T> RustcInternal for &T
 where
     T: RustcInternal,
diff --git a/compiler/rustc_smir/src/rustc_internal/pretty.rs b/compiler/rustc_smir/src/rustc_internal/pretty.rs
index 3ef2d28ea47..c0dce08b0d3 100644
--- a/compiler/rustc_smir/src/rustc_internal/pretty.rs
+++ b/compiler/rustc_smir/src/rustc_internal/pretty.rs
@@ -14,7 +14,7 @@ pub fn write_smir_pretty<'tcx, W: io::Write>(tcx: TyCtxt<'tcx>, w: &mut W) -> io
     )?;
     let _ = run(tcx, || {
         let items = stable_mir::all_local_items();
-        let _ = items.iter().map(|item| -> io::Result<()> { item.dump(w) }).collect::<Vec<_>>();
+        let _ = items.iter().map(|item| -> io::Result<()> { item.emit_mir(w) }).collect::<Vec<_>>();
     });
     Ok(())
 }
diff --git a/compiler/rustc_smir/src/rustc_smir/context.rs b/compiler/rustc_smir/src/rustc_smir/context.rs
index d427e5fb88d..d39a3788d4c 100644
--- a/compiler/rustc_smir/src/rustc_smir/context.rs
+++ b/compiler/rustc_smir/src/rustc_smir/context.rs
@@ -19,7 +19,7 @@ use stable_mir::abi::{FnAbi, Layout, LayoutShape};
 use stable_mir::compiler_interface::Context;
 use stable_mir::mir::alloc::GlobalAlloc;
 use stable_mir::mir::mono::{InstanceDef, StaticDef};
-use stable_mir::mir::Body;
+use stable_mir::mir::{Body, Place};
 use stable_mir::target::{MachineInfo, MachineSize};
 use stable_mir::ty::{
     AdtDef, AdtKind, Allocation, ClosureDef, ClosureKind, Const, FieldDef, FnDef, ForeignDef,
@@ -423,7 +423,7 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         def_ty.instantiate(tables.tcx, args).stable(&mut *tables)
     }
 
-    fn const_literal(&self, cnst: &stable_mir::ty::Const) -> String {
+    fn const_pretty(&self, cnst: &stable_mir::ty::Const) -> String {
         let mut tables = self.0.borrow_mut();
         let tcx = tables.tcx;
         cnst.internal(&mut *tables, tcx).to_string()
@@ -434,6 +434,11 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         tables.tcx.def_span(tables[def_id]).stable(&mut *tables)
     }
 
+    fn ty_pretty(&self, ty: stable_mir::ty::Ty) -> String {
+        let tables = self.0.borrow_mut();
+        tables.types[ty].to_string()
+    }
+
     fn ty_kind(&self, ty: stable_mir::ty::Ty) -> TyKind {
         let mut tables = self.0.borrow_mut();
         tables.types[ty].kind().stable(&mut *tables)
@@ -654,6 +659,12 @@ impl<'tcx> Context for TablesWrapper<'tcx> {
         let tcx = tables.tcx;
         id.internal(&mut *tables, tcx).0.stable(&mut *tables)
     }
+
+    fn place_pretty(&self, place: &Place) -> String {
+        let mut tables = self.0.borrow_mut();
+        let tcx = tables.tcx;
+        format!("{:?}", place.internal(&mut *tables, tcx))
+    }
 }
 
 pub struct TablesWrapper<'tcx>(pub RefCell<Tables<'tcx>>);
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 8b911a41a11..b6c07e8737f 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -207,6 +207,7 @@ symbols! {
         FromResidual,
         FsOpenOptions,
         FsPermissions,
+        FusedIterator,
         Future,
         FutureOutput,
         GlobalAlloc,
@@ -674,6 +675,7 @@ symbols! {
         deref_method,
         deref_mut,
         deref_mut_method,
+        deref_patterns,
         deref_target,
         derive,
         derive_const,
@@ -689,6 +691,7 @@ symbols! {
         dispatch_from_dyn,
         div,
         div_assign,
+        diverging_block_default,
         do_not_recommend,
         doc,
         doc_alias,
@@ -814,9 +817,7 @@ symbols! {
         fadd_algebraic,
         fadd_fast,
         fake_variadic,
-        fallback_to_never,
-        fallback_to_niko,
-        fallback_to_unit,
+        fallback,
         fdiv_algebraic,
         fdiv_fast,
         feature,
@@ -885,6 +886,7 @@ symbols! {
         fsub_algebraic,
         fsub_fast,
         fundamental,
+        fused_iterator,
         future,
         future_trait,
         gdb_script_file,
@@ -1227,6 +1229,7 @@ symbols! {
         new_v1,
         new_v1_formatted,
         next,
+        niko,
         nll,
         no,
         no_builtins,
@@ -1235,7 +1238,6 @@ symbols! {
         no_crate_inject,
         no_debug,
         no_default_passes,
-        no_fallback,
         no_implicit_prelude,
         no_inline,
         no_link,
@@ -1333,6 +1335,7 @@ symbols! {
         poll,
         poll_next,
         post_dash_lto: "post-lto",
+        postfix_match,
         powerpc_target_feature,
         powf128,
         powf16,
@@ -1553,7 +1556,7 @@ symbols! {
         rustc_mir,
         rustc_must_implement_one_of,
         rustc_never_returns_null_ptr,
-        rustc_never_type_mode,
+        rustc_never_type_options,
         rustc_no_mir_inline,
         rustc_nonnull_optimization_guaranteed,
         rustc_nounwind,
diff --git a/compiler/rustc_symbol_mangling/src/test.rs b/compiler/rustc_symbol_mangling/src/test.rs
index 6766080a54f..f0fb87fe83c 100644
--- a/compiler/rustc_symbol_mangling/src/test.rs
+++ b/compiler/rustc_symbol_mangling/src/test.rs
@@ -25,7 +25,7 @@ pub fn report_symbol_names(tcx: TyCtxt<'_>) {
         let mut symbol_names = SymbolNamesTest { tcx };
         let crate_items = tcx.hir_crate_items(());
 
-        for id in crate_items.items() {
+        for id in crate_items.free_items() {
             symbol_names.process_attrs(id.owner_id.def_id);
         }
 
diff --git a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
index 51e2c96120c..76a5d942c66 100644
--- a/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
+++ b/compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
@@ -18,7 +18,7 @@ use rustc_middle::ty::{
 use rustc_middle::ty::{GenericArg, GenericArgKind, GenericArgsRef};
 use rustc_span::def_id::DefId;
 use rustc_span::sym;
-use rustc_target::abi::call::{Conv, FnAbi};
+use rustc_target::abi::call::{Conv, FnAbi, PassMode};
 use rustc_target::abi::Integer;
 use rustc_target::spec::abi::Abi;
 use std::fmt::Write as _;
@@ -1040,19 +1040,27 @@ pub fn typeid_for_fnabi<'tcx>(
     typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options));
 
     // Encode the parameter types
+
+    // We erase ZSTs as we go if the argument is skipped. This is an implementation detail of how
+    // MIR is currently treated by rustc, and subject to change in the future. Specifically, MIR
+    // interpretation today will allow skipped arguments to simply not be passed at a call-site.
     if !fn_abi.c_variadic {
-        if !fn_abi.args.is_empty() {
-            for arg in fn_abi.args.iter() {
-                let ty = transform_ty(tcx, arg.layout.ty, transform_ty_options);
-                typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options));
-            }
-        } else {
+        let mut pushed_arg = false;
+        for arg in fn_abi.args.iter().filter(|arg| arg.mode != PassMode::Ignore) {
+            pushed_arg = true;
+            let ty = transform_ty(tcx, arg.layout.ty, transform_ty_options);
+            typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options));
+        }
+        if !pushed_arg {
             // Empty parameter lists, whether declared as () or conventionally as (void), are
             // encoded with a void parameter specifier "v".
             typeid.push('v');
         }
     } else {
         for n in 0..fn_abi.fixed_count as usize {
+            if fn_abi.args[n].mode == PassMode::Ignore {
+                continue;
+            }
             let ty = transform_ty(tcx, fn_abi.args[n].layout.ty, transform_ty_options);
             typeid.push_str(&encode_ty(tcx, ty, &mut dict, encode_ty_options));
         }
diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs
index 941d767b850..966da2c5eda 100644
--- a/compiler/rustc_target/src/spec/mod.rs
+++ b/compiler/rustc_target/src/spec/mod.rs
@@ -1621,6 +1621,7 @@ supported_targets! {
     ("riscv32i-unknown-none-elf", riscv32i_unknown_none_elf),
     ("riscv32im-risc0-zkvm-elf", riscv32im_risc0_zkvm_elf),
     ("riscv32im-unknown-none-elf", riscv32im_unknown_none_elf),
+    ("riscv32ima-unknown-none-elf", riscv32ima_unknown_none_elf),
     ("riscv32imc-unknown-none-elf", riscv32imc_unknown_none_elf),
     ("riscv32imc-esp-espidf", riscv32imc_esp_espidf),
     ("riscv32imac-esp-espidf", riscv32imac_esp_espidf),
@@ -2091,6 +2092,9 @@ pub struct TargetOptions {
     /// compiling `rustc` will be used instead (or llvm if it is not set).
     ///
     /// N.B. when *using* the compiler, backend can always be overridden with `-Zcodegen-backend`.
+    ///
+    /// This was added by WaffleLapkin in #116793. The motivation is a rustc fork that requires a
+    /// custom codegen backend for a particular target.
     pub default_codegen_backend: Option<StaticCow<str>>,
 
     /// Whether to generate trap instructions in places where optimization would
diff --git a/compiler/rustc_target/src/spec/targets/riscv32ima_unknown_none_elf.rs b/compiler/rustc_target/src/spec/targets/riscv32ima_unknown_none_elf.rs
new file mode 100644
index 00000000000..9acf6a3b5a0
--- /dev/null
+++ b/compiler/rustc_target/src/spec/targets/riscv32ima_unknown_none_elf.rs
@@ -0,0 +1,29 @@
+use crate::spec::{Cc, LinkerFlavor, Lld, PanicStrategy, RelocModel, Target, TargetOptions};
+
+pub fn target() -> Target {
+    Target {
+        data_layout: "e-m:e-p:32:32-i64:64-n32-S128".into(),
+        llvm_target: "riscv32".into(),
+        metadata: crate::spec::TargetMetadata {
+            description: None,
+            tier: None,
+            host_tools: None,
+            std: None,
+        },
+        pointer_width: 32,
+        arch: "riscv32".into(),
+
+        options: TargetOptions {
+            linker_flavor: LinkerFlavor::Gnu(Cc::No, Lld::Yes),
+            linker: Some("rust-lld".into()),
+            cpu: "generic-rv32".into(),
+            max_atomic_width: Some(32),
+            features: "+m,+a".into(),
+            panic_strategy: PanicStrategy::Abort,
+            relocation_model: RelocModel::Static,
+            emit_debug_gdb_scripts: false,
+            eh_frame_header: false,
+            ..Default::default()
+        },
+    }
+}
diff --git a/compiler/rustc_trait_selection/messages.ftl b/compiler/rustc_trait_selection/messages.ftl
index 0dcba0e05f7..f96bd985237 100644
--- a/compiler/rustc_trait_selection/messages.ftl
+++ b/compiler/rustc_trait_selection/messages.ftl
@@ -19,6 +19,9 @@ trait_selection_closure_kind_mismatch = expected a closure that implements the `
 
 trait_selection_closure_kind_requirement = the requirement to implement `{$trait_prefix}{$expected}` derives from here
 
+trait_selection_disallowed_positional_argument = positional format arguments are not allowed here
+    .help = only named format arguments with the name of one of the generic types are allowed in this context
+
 trait_selection_dump_vtable_entries = vtable entries for `{$trait_ref}`: {$entries}
 
 trait_selection_empty_on_clause_in_rustc_on_unimplemented = empty `on`-clause in `#[rustc_on_unimplemented]`
@@ -30,6 +33,9 @@ trait_selection_ignored_diagnostic_option = `{$option_name}` is ignored due to p
 
 trait_selection_inherent_projection_normalization_overflow = overflow evaluating associated type `{$ty}`
 
+trait_selection_invalid_format_specifier = invalid format specifier
+    .help = no format specifier are supported in this position
+
 trait_selection_invalid_on_clause_in_rustc_on_unimplemented = invalid `on`-clause in `#[rustc_on_unimplemented]`
     .label = invalid on-clause here
 
@@ -60,3 +66,6 @@ trait_selection_unable_to_construct_constant_value = unable to construct a const
 
 trait_selection_unknown_format_parameter_for_on_unimplemented_attr = there is no parameter `{$argument_name}` on trait `{$trait_name}`
     .help = expect either a generic argument name or {"`{Self}`"} as format argument
+
+trait_selection_wrapped_parser_error = {$description}
+    .label = {$label}
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
index 9f33dce2a6d..d92bae2528f 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/mod.rs
@@ -215,6 +215,13 @@ pub(super) trait GoalKind<'tcx>:
         goal: Goal<'tcx, Self>,
     ) -> QueryResult<'tcx>;
 
+    /// A coroutine (that comes from a `gen` desugaring) is known to implement
+    /// `FusedIterator`
+    fn consider_builtin_fused_iterator_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
+
     fn consider_builtin_async_iterator_candidate(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
@@ -497,6 +504,8 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
             G::consider_builtin_future_candidate(self, goal)
         } else if lang_items.iterator_trait() == Some(trait_def_id) {
             G::consider_builtin_iterator_candidate(self, goal)
+        } else if lang_items.fused_iterator_trait() == Some(trait_def_id) {
+            G::consider_builtin_fused_iterator_candidate(self, goal)
         } else if lang_items.async_iterator_trait() == Some(trait_def_id) {
             G::consider_builtin_async_iterator_candidate(self, goal)
         } else if lang_items.coroutine_trait() == Some(trait_def_id) {
diff --git a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
index faf8c55c475..80c31831462 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs
@@ -6,7 +6,7 @@ use rustc_hir::{def_id::DefId, Movability, Mutability};
 use rustc_infer::traits::query::NoSolution;
 use rustc_middle::traits::solve::Goal;
 use rustc_middle::ty::{
-    self, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt,
+    self, ToPredicate, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable,
 };
 use rustc_span::sym;
 
@@ -73,8 +73,8 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
 
         ty::CoroutineWitness(def_id, args) => Ok(ecx
             .tcx()
-            .coroutine_hidden_types(def_id)
-            .map(|bty| replace_erased_lifetimes_with_bound_vars(tcx, bty.instantiate(tcx, args)))
+            .bound_coroutine_hidden_types(def_id)
+            .map(|bty| bty.instantiate(tcx, args))
             .collect()),
 
         // For `PhantomData<T>`, we pass `T`.
@@ -93,27 +93,6 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
     }
 }
 
-pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    ty: Ty<'tcx>,
-) -> ty::Binder<'tcx, Ty<'tcx>> {
-    debug_assert!(!ty.has_bound_regions());
-    let mut counter = 0;
-    let ty = tcx.fold_regions(ty, |r, current_depth| match r.kind() {
-        ty::ReErased => {
-            let br = ty::BoundRegion { var: ty::BoundVar::from_u32(counter), kind: ty::BrAnon };
-            counter += 1;
-            ty::Region::new_bound(tcx, current_depth, br)
-        }
-        // All free regions should be erased here.
-        r => bug!("unexpected region: {r:?}"),
-    });
-    let bound_vars = tcx.mk_bound_variable_kinds_from_iter(
-        (0..counter).map(|_| ty::BoundVariableKind::Region(ty::BrAnon)),
-    );
-    ty::Binder::bind_with_vars(ty, bound_vars)
-}
-
 #[instrument(level = "debug", skip(ecx), ret)]
 pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
     ecx: &EvalCtxt<'_, 'tcx>,
@@ -241,13 +220,8 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
         // impl Copy/Clone for CoroutineWitness where T: Copy/Clone forall T in coroutine_hidden_types
         ty::CoroutineWitness(def_id, args) => Ok(ecx
             .tcx()
-            .coroutine_hidden_types(def_id)
-            .map(|bty| {
-                replace_erased_lifetimes_with_bound_vars(
-                    ecx.tcx(),
-                    bty.instantiate(ecx.tcx(), args),
-                )
-            })
+            .bound_coroutine_hidden_types(def_id)
+            .map(|bty| bty.instantiate(ecx.tcx(), args))
             .collect()),
     }
 }
diff --git a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
index 85bb6338daf..66688893235 100644
--- a/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/normalizes_to/mod.rs
@@ -647,6 +647,13 @@ impl<'tcx> assembly::GoalKind<'tcx> for NormalizesTo<'tcx> {
         )
     }
 
+    fn consider_builtin_fused_iterator_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`FusedIterator` does not have an associated type: {:?}", goal);
+    }
+
     fn consider_builtin_async_iterator_candidate(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index c252ad76dfe..184ba31f19d 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -456,6 +456,28 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
         ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
     }
 
+    fn consider_builtin_fused_iterator_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        if goal.predicate.polarity != ty::ImplPolarity::Positive {
+            return Err(NoSolution);
+        }
+
+        let ty::Coroutine(def_id, _) = *goal.predicate.self_ty().kind() else {
+            return Err(NoSolution);
+        };
+
+        // Coroutines are not iterators unless they come from `gen` desugaring
+        let tcx = ecx.tcx();
+        if !tcx.coroutine_is_gen(def_id) {
+            return Err(NoSolution);
+        }
+
+        // Gen coroutines unconditionally implement `FusedIterator`
+        ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
+    }
+
     fn consider_builtin_async_iterator_candidate(
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
index 745ddfc08af..5fccc769785 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
@@ -367,6 +367,23 @@ pub struct UnknownFormatParameterForOnUnimplementedAttr {
     trait_name: Symbol,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(trait_selection_disallowed_positional_argument)]
+#[help]
+pub struct DisallowedPositionalArgument;
+
+#[derive(LintDiagnostic)]
+#[diag(trait_selection_invalid_format_specifier)]
+#[help]
+pub struct InvalidFormatSpecifier;
+
+#[derive(LintDiagnostic)]
+#[diag(trait_selection_wrapped_parser_error)]
+pub struct WrappedParserError {
+    description: String,
+    label: String,
+}
+
 impl<'tcx> OnUnimplementedDirective {
     fn parse(
         tcx: TyCtxt<'tcx>,
@@ -758,64 +775,108 @@ impl<'tcx> OnUnimplementedFormatString {
         let trait_name = tcx.item_name(trait_def_id);
         let generics = tcx.generics_of(item_def_id);
         let s = self.symbol.as_str();
-        let parser = Parser::new(s, None, None, false, ParseMode::Format);
+        let mut parser = Parser::new(s, None, None, false, ParseMode::Format);
         let mut result = Ok(());
-        for token in parser {
+        for token in &mut parser {
             match token {
                 Piece::String(_) => (), // Normal string, no need to check it
-                Piece::NextArgument(a) => match a.position {
-                    Position::ArgumentNamed(s) => {
-                        match Symbol::intern(s) {
-                            // `{ThisTraitsName}` is allowed
-                            s if s == trait_name && !self.is_diagnostic_namespace_variant => (),
-                            s if ALLOWED_FORMAT_SYMBOLS.contains(&s)
-                                && !self.is_diagnostic_namespace_variant =>
-                            {
-                                ()
-                            }
-                            // So is `{A}` if A is a type parameter
-                            s if generics.params.iter().any(|param| param.name == s) => (),
-                            s => {
-                                if self.is_diagnostic_namespace_variant {
-                                    tcx.emit_node_span_lint(
-                                        UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
-                                        tcx.local_def_id_to_hir_id(item_def_id.expect_local()),
-                                        self.span,
-                                        UnknownFormatParameterForOnUnimplementedAttr {
-                                            argument_name: s,
-                                            trait_name,
-                                        },
-                                    );
-                                } else {
-                                    result = Err(struct_span_code_err!(
-                                        tcx.dcx(),
-                                        self.span,
-                                        E0230,
-                                        "there is no parameter `{}` on {}",
-                                        s,
-                                        if trait_def_id == item_def_id {
-                                            format!("trait `{trait_name}`")
-                                        } else {
-                                            "impl".to_string()
-                                        }
-                                    )
-                                    .emit());
+                Piece::NextArgument(a) => {
+                    let format_spec = a.format;
+                    if self.is_diagnostic_namespace_variant
+                        && (format_spec.ty_span.is_some()
+                            || format_spec.width_span.is_some()
+                            || format_spec.precision_span.is_some()
+                            || format_spec.fill_span.is_some())
+                    {
+                        tcx.emit_node_span_lint(
+                            UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                            tcx.local_def_id_to_hir_id(item_def_id.expect_local()),
+                            self.span,
+                            InvalidFormatSpecifier,
+                        );
+                    }
+                    match a.position {
+                        Position::ArgumentNamed(s) => {
+                            match Symbol::intern(s) {
+                                // `{ThisTraitsName}` is allowed
+                                s if s == trait_name && !self.is_diagnostic_namespace_variant => (),
+                                s if ALLOWED_FORMAT_SYMBOLS.contains(&s)
+                                    && !self.is_diagnostic_namespace_variant =>
+                                {
+                                    ()
+                                }
+                                // So is `{A}` if A is a type parameter
+                                s if generics.params.iter().any(|param| param.name == s) => (),
+                                s => {
+                                    if self.is_diagnostic_namespace_variant {
+                                        tcx.emit_node_span_lint(
+                                            UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                                            tcx.local_def_id_to_hir_id(item_def_id.expect_local()),
+                                            self.span,
+                                            UnknownFormatParameterForOnUnimplementedAttr {
+                                                argument_name: s,
+                                                trait_name,
+                                            },
+                                        );
+                                    } else {
+                                        result = Err(struct_span_code_err!(
+                                            tcx.dcx(),
+                                            self.span,
+                                            E0230,
+                                            "there is no parameter `{}` on {}",
+                                            s,
+                                            if trait_def_id == item_def_id {
+                                                format!("trait `{trait_name}`")
+                                            } else {
+                                                "impl".to_string()
+                                            }
+                                        )
+                                        .emit());
+                                    }
                                 }
                             }
                         }
+                        // `{:1}` and `{}` are not to be used
+                        Position::ArgumentIs(..) | Position::ArgumentImplicitlyIs(_) => {
+                            if self.is_diagnostic_namespace_variant {
+                                tcx.emit_node_span_lint(
+                                    UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                                    tcx.local_def_id_to_hir_id(item_def_id.expect_local()),
+                                    self.span,
+                                    DisallowedPositionalArgument,
+                                );
+                            } else {
+                                let reported = struct_span_code_err!(
+                                    tcx.dcx(),
+                                    self.span,
+                                    E0231,
+                                    "only named generic parameters are allowed"
+                                )
+                                .emit();
+                                result = Err(reported);
+                            }
+                        }
                     }
-                    // `{:1}` and `{}` are not to be used
-                    Position::ArgumentIs(..) | Position::ArgumentImplicitlyIs(_) => {
-                        let reported = struct_span_code_err!(
-                            tcx.dcx(),
-                            self.span,
-                            E0231,
-                            "only named generic parameters are allowed"
-                        )
-                        .emit();
-                        result = Err(reported);
-                    }
-                },
+                }
+            }
+        }
+        // we cannot return errors from processing the format string as hard error here
+        // as the diagnostic namespace gurantees that malformed input cannot cause an error
+        //
+        // if we encounter any error while processing we nevertheless want to show it as warning
+        // so that users are aware that something is not correct
+        for e in parser.errors {
+            if self.is_diagnostic_namespace_variant {
+                tcx.emit_node_span_lint(
+                    UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                    tcx.local_def_id_to_hir_id(item_def_id.expect_local()),
+                    self.span,
+                    WrappedParserError { description: e.description, label: e.label },
+                );
+            } else {
+                let reported =
+                    struct_span_code_err!(tcx.dcx(), self.span, E0231, "{}", e.description,).emit();
+                result = Err(reported);
             }
         }
 
@@ -853,9 +914,9 @@ impl<'tcx> OnUnimplementedFormatString {
         let empty_string = String::new();
 
         let s = self.symbol.as_str();
-        let parser = Parser::new(s, None, None, false, ParseMode::Format);
+        let mut parser = Parser::new(s, None, None, false, ParseMode::Format);
         let item_context = (options.get(&sym::ItemContext)).unwrap_or(&empty_string);
-        parser
+        let constructed_message = (&mut parser)
             .map(|p| match p {
                 Piece::String(s) => s.to_owned(),
                 Piece::NextArgument(a) => match a.position {
@@ -895,9 +956,29 @@ impl<'tcx> OnUnimplementedFormatString {
                             }
                         }
                     }
+                    Position::ArgumentImplicitlyIs(_) if self.is_diagnostic_namespace_variant => {
+                        String::from("{}")
+                    }
+                    Position::ArgumentIs(idx) if self.is_diagnostic_namespace_variant => {
+                        format!("{{{idx}}}")
+                    }
                     _ => bug!("broken on_unimplemented {:?} - bad format arg", self.symbol),
                 },
             })
-            .collect()
+            .collect();
+        // we cannot return errors from processing the format string as hard error here
+        // as the diagnostic namespace gurantees that malformed input cannot cause an error
+        //
+        // if we encounter any error while processing the format string
+        // we don't want to show the potentially half assembled formated string,
+        // therefore we fall back to just showing the input string in this case
+        //
+        // The actual parser errors are emitted earlier
+        // as lint warnings in OnUnimplementedFormatString::verify
+        if self.is_diagnostic_namespace_variant && !parser.errors.is_empty() {
+            String::from(s)
+        } else {
+            constructed_message
+        }
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index d19c2bd1f60..00d00496947 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -1098,8 +1098,11 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                         ))
                     }
                     ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => {
-                        self.tcx.item_bounds(def_id).instantiate(self.tcx, args).iter().find_map(
-                            |pred| {
+                        self.tcx
+                            .item_super_predicates(def_id)
+                            .instantiate(self.tcx, args)
+                            .iter()
+                            .find_map(|pred| {
                                 if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
                         && Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
                         // args tuple will always be args[1]
@@ -1113,8 +1116,7 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                                 } else {
                                     None
                                 }
-                            },
-                        )
+                            })
                     }
                     ty::Dynamic(data, _, ty::Dyn) => {
                         data.iter().find_map(|pred| {
diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
index 49091e53be7..9fb4577fb21 100644
--- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
@@ -118,6 +118,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     self.assemble_future_candidates(obligation, &mut candidates);
                 } else if lang_items.iterator_trait() == Some(def_id) {
                     self.assemble_iterator_candidates(obligation, &mut candidates);
+                } else if lang_items.fused_iterator_trait() == Some(def_id) {
+                    self.assemble_fused_iterator_candidates(obligation, &mut candidates);
                 } else if lang_items.async_iterator_trait() == Some(def_id) {
                     self.assemble_async_iterator_candidates(obligation, &mut candidates);
                 } else if lang_items.async_fn_kind_helper() == Some(def_id) {
@@ -302,14 +304,31 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         candidates: &mut SelectionCandidateSet<'tcx>,
     ) {
         let self_ty = obligation.self_ty().skip_binder();
-        if let ty::Coroutine(did, ..) = self_ty.kind() {
-            // gen constructs get lowered to a special kind of coroutine that
-            // should directly `impl Iterator`.
-            if self.tcx().coroutine_is_gen(*did) {
-                debug!(?self_ty, ?obligation, "assemble_iterator_candidates",);
+        // gen constructs get lowered to a special kind of coroutine that
+        // should directly `impl Iterator`.
+        if let ty::Coroutine(did, ..) = self_ty.kind()
+            && self.tcx().coroutine_is_gen(*did)
+        {
+            debug!(?self_ty, ?obligation, "assemble_iterator_candidates",);
 
-                candidates.vec.push(IteratorCandidate);
-            }
+            candidates.vec.push(IteratorCandidate);
+        }
+    }
+
+    fn assemble_fused_iterator_candidates(
+        &mut self,
+        obligation: &PolyTraitObligation<'tcx>,
+        candidates: &mut SelectionCandidateSet<'tcx>,
+    ) {
+        let self_ty = obligation.self_ty().skip_binder();
+        // gen constructs get lowered to a special kind of coroutine that
+        // should directly `impl FusedIterator`.
+        if let ty::Coroutine(did, ..) = self_ty.kind()
+            && self.tcx().coroutine_is_gen(*did)
+        {
+            debug!(?self_ty, ?obligation, "assemble_fused_iterator_candidates",);
+
+            candidates.vec.push(BuiltinCandidate { has_nested: false });
         }
     }
 
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index 51fc223a5d1..6f16194d44f 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -14,7 +14,7 @@ use rustc_infer::infer::{DefineOpaqueTypes, InferOk};
 use rustc_middle::traits::{BuiltinImplSource, SignatureMismatchData};
 use rustc_middle::ty::{
     self, GenericArgs, GenericArgsRef, GenericParamDefKind, ToPolyTraitRef, ToPredicate,
-    TraitPredicate, Ty, TyCtxt, TypeVisitableExt,
+    TraitPredicate, Ty, TyCtxt,
 };
 use rustc_span::def_id::DefId;
 
@@ -267,6 +267,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 self.copy_clone_conditions(obligation)
             } else if Some(trait_def) == lang_items.clone_trait() {
                 self.copy_clone_conditions(obligation)
+            } else if Some(trait_def) == lang_items.fused_iterator_trait() {
+                self.fused_iterator_conditions(obligation)
             } else {
                 bug!("unexpected builtin trait {:?}", trait_def)
             };
@@ -1438,10 +1440,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 }
                 ty::CoroutineWitness(def_id, args) => {
                     let tcx = self.tcx();
-                    stack.extend(tcx.coroutine_hidden_types(def_id).map(|bty| {
-                        let ty = bty.instantiate(tcx, args);
-                        debug_assert!(!ty.has_bound_regions());
-                        ty
+                    stack.extend(tcx.bound_coroutine_hidden_types(def_id).map(|bty| {
+                        self.infcx.enter_forall_and_leak_universe(bty.instantiate(tcx, args))
                     }))
                 }
 
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 6460613d7d5..adbc7d12a64 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1617,21 +1617,17 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 _ => return ControlFlow::Continue(()),
             };
 
-            for bound in
-                self.tcx().item_bounds(alias_ty.def_id).instantiate(self.tcx(), alias_ty.args)
-            {
-                // HACK: On subsequent recursions, we only care about bounds that don't
-                // share the same type as `self_ty`. This is because for truly rigid
-                // projections, we will never be able to equate, e.g. `<T as Tr>::A`
-                // with `<<T as Tr>::A as Tr>::A`.
-                if in_parent_alias_type {
-                    match bound.kind().skip_binder() {
-                        ty::ClauseKind::Trait(tr) if tr.self_ty() == self_ty => continue,
-                        ty::ClauseKind::Projection(p) if p.self_ty() == self_ty => continue,
-                        _ => {}
-                    }
-                }
+            // HACK: On subsequent recursions, we only care about bounds that don't
+            // share the same type as `self_ty`. This is because for truly rigid
+            // projections, we will never be able to equate, e.g. `<T as Tr>::A`
+            // with `<<T as Tr>::A as Tr>::A`.
+            let relevant_bounds = if in_parent_alias_type {
+                self.tcx().item_non_self_assumptions(alias_ty.def_id)
+            } else {
+                self.tcx().item_super_predicates(alias_ty.def_id)
+            };
 
+            for bound in relevant_bounds.instantiate(self.tcx(), alias_ty.args) {
                 for_each(self, bound, idx)?;
                 idx += 1;
             }
@@ -2263,6 +2259,20 @@ impl<'tcx> SelectionContext<'_, 'tcx> {
         }
     }
 
+    fn fused_iterator_conditions(
+        &mut self,
+        obligation: &PolyTraitObligation<'tcx>,
+    ) -> BuiltinImplConditions<'tcx> {
+        let self_ty = self.infcx.shallow_resolve(obligation.self_ty().skip_binder());
+        if let ty::Coroutine(did, ..) = *self_ty.kind()
+            && self.tcx().coroutine_is_gen(did)
+        {
+            BuiltinImplConditions::Where(ty::Binder::dummy(Vec::new()))
+        } else {
+            BuiltinImplConditions::None
+        }
+    }
+
     /// For default impls, we need to break apart a type into its
     /// "constituent types" -- meaning, the types that it contains.
     ///
diff --git a/compiler/rustc_type_ir/src/flags.rs b/compiler/rustc_type_ir/src/flags.rs
index b38ef2ad84d..cd199222d90 100644
--- a/compiler/rustc_type_ir/src/flags.rs
+++ b/compiler/rustc_type_ir/src/flags.rs
@@ -85,7 +85,7 @@ bitflags! {
                                           | TypeFlags::HAS_TY_INHERENT.bits()
                                           | TypeFlags::HAS_CT_PROJECTION.bits();
 
-        /// Is an error type/const reachable?
+        /// Is an error type/lifetime/const reachable?
         const HAS_ERROR                   = 1 << 15;
 
         /// Does this have any region that "appears free" in the type?
diff --git a/compiler/stable_mir/src/compiler_interface.rs b/compiler/stable_mir/src/compiler_interface.rs
index f53dbcfbd96..8ed34fab54d 100644
--- a/compiler/stable_mir/src/compiler_interface.rs
+++ b/compiler/stable_mir/src/compiler_interface.rs
@@ -8,7 +8,7 @@ use std::cell::Cell;
 use crate::abi::{FnAbi, Layout, LayoutShape};
 use crate::mir::alloc::{AllocId, GlobalAlloc};
 use crate::mir::mono::{Instance, InstanceDef, StaticDef};
-use crate::mir::Body;
+use crate::mir::{Body, Place};
 use crate::target::MachineInfo;
 use crate::ty::{
     AdtDef, AdtKind, Allocation, ClosureDef, ClosureKind, Const, FieldDef, FnDef, ForeignDef,
@@ -126,12 +126,15 @@ pub trait Context {
     fn def_ty_with_args(&self, item: DefId, args: &GenericArgs) -> Ty;
 
     /// Returns literal value of a const as a string.
-    fn const_literal(&self, cnst: &Const) -> String;
+    fn const_pretty(&self, cnst: &Const) -> String;
 
     /// `Span` of an item
     fn span_of_an_item(&self, def_id: DefId) -> Span;
 
     /// Obtain the representation of a type.
+    fn ty_pretty(&self, ty: Ty) -> String;
+
+    /// Obtain the representation of a type.
     fn ty_kind(&self, ty: Ty) -> TyKind;
 
     // Get the discriminant Ty for this Ty if there's one.
@@ -205,6 +208,9 @@ pub trait Context {
 
     /// Get the layout shape.
     fn layout_shape(&self, id: Layout) -> LayoutShape;
+
+    /// Get a debug string representation of a place.
+    fn place_pretty(&self, place: &Place) -> String;
 }
 
 // A thread local variable that stores a pointer to the tables mapping between TyCtxt
diff --git a/compiler/stable_mir/src/lib.rs b/compiler/stable_mir/src/lib.rs
index d849c834ae0..d1a2948ea77 100644
--- a/compiler/stable_mir/src/lib.rs
+++ b/compiler/stable_mir/src/lib.rs
@@ -27,7 +27,6 @@ use crate::compiler_interface::with;
 pub use crate::crate_def::CrateDef;
 pub use crate::crate_def::DefId;
 pub use crate::error::*;
-use crate::mir::pretty::function_name;
 use crate::mir::Body;
 use crate::mir::Mutability;
 use crate::ty::{ForeignModuleDef, ImplDef, IndexedVal, Span, TraitDef, Ty};
@@ -148,9 +147,8 @@ impl CrateItem {
         with(|cx| cx.is_foreign_item(self.0))
     }
 
-    pub fn dump<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
-        writeln!(w, "{}", function_name(*self))?;
-        self.body().dump(w)
+    pub fn emit_mir<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
+        self.body().dump(w, &self.name())
     }
 }
 
diff --git a/compiler/stable_mir/src/mir/body.rs b/compiler/stable_mir/src/mir/body.rs
index ae8e71bb950..e4a012d8c47 100644
--- a/compiler/stable_mir/src/mir/body.rs
+++ b/compiler/stable_mir/src/mir/body.rs
@@ -1,10 +1,11 @@
-use crate::mir::pretty::{function_body, pretty_statement, pretty_terminator};
+use crate::mir::pretty::function_body;
 use crate::ty::{
     AdtDef, ClosureDef, Const, CoroutineDef, GenericArgs, Movability, Region, RigidTy, Ty, TyKind,
     VariantIdx,
 };
 use crate::{Error, Opaque, Span, Symbol};
 use std::io;
+
 /// The SMIR representation of a single function.
 #[derive(Clone, Debug)]
 pub struct Body {
@@ -90,28 +91,9 @@ impl Body {
         self.locals.iter().enumerate()
     }
 
-    pub fn dump<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
-        writeln!(w, "{}", function_body(self))?;
-        self.blocks
-            .iter()
-            .enumerate()
-            .map(|(index, block)| -> io::Result<()> {
-                writeln!(w, "    bb{}: {{", index)?;
-                let _ = block
-                    .statements
-                    .iter()
-                    .map(|statement| -> io::Result<()> {
-                        writeln!(w, "{}", pretty_statement(&statement.kind))?;
-                        Ok(())
-                    })
-                    .collect::<Vec<_>>();
-                pretty_terminator(&block.terminator.kind, w)?;
-                writeln!(w, "").unwrap();
-                writeln!(w, "    }}").unwrap();
-                Ok(())
-            })
-            .collect::<Result<Vec<_>, _>>()?;
-        Ok(())
+    /// Emit the body using the provided name for the signature.
+    pub fn dump<W: io::Write>(&self, w: &mut W, fn_name: &str) -> io::Result<()> {
+        function_body(w, self, fn_name)
     }
 
     pub fn spread_arg(&self) -> Option<Local> {
@@ -674,7 +656,7 @@ pub enum Operand {
     Constant(Constant),
 }
 
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Eq, PartialEq)]
 pub struct Place {
     pub local: Local,
     /// projection out of a place (access a field, deref a pointer, etc)
diff --git a/compiler/stable_mir/src/mir/mono.rs b/compiler/stable_mir/src/mir/mono.rs
index 38e5776c48c..aafa89c03e0 100644
--- a/compiler/stable_mir/src/mir/mono.rs
+++ b/compiler/stable_mir/src/mir/mono.rs
@@ -4,6 +4,7 @@ use crate::mir::Body;
 use crate::ty::{Allocation, ClosureDef, ClosureKind, FnDef, GenericArgs, IndexedVal, Ty};
 use crate::{with, CrateItem, DefId, Error, ItemKind, Opaque, Symbol};
 use std::fmt::{Debug, Formatter};
+use std::io;
 
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum MonoItem {
@@ -157,6 +158,11 @@ impl Instance {
     pub fn try_const_eval(&self, const_ty: Ty) -> Result<Allocation, Error> {
         with(|cx| cx.eval_instance(self.def, const_ty))
     }
+
+    /// Emit the body of this instance if it has one.
+    pub fn emit_mir<W: io::Write>(&self, w: &mut W) -> io::Result<()> {
+        if let Some(body) = self.body() { body.dump(w, &self.name()) } else { Ok(()) }
+    }
 }
 
 impl Debug for Instance {
diff --git a/compiler/stable_mir/src/mir/pretty.rs b/compiler/stable_mir/src/mir/pretty.rs
index 8b7b488d312..4ac4833add7 100644
--- a/compiler/stable_mir/src/mir/pretty.rs
+++ b/compiler/stable_mir/src/mir/pretty.rs
@@ -1,185 +1,193 @@
-use crate::crate_def::CrateDef;
-use crate::mir::{Operand, Rvalue, StatementKind, UnwindAction};
-use crate::ty::{DynKind, FloatTy, IntTy, RigidTy, TyKind, UintTy};
-use crate::{with, Body, CrateItem, Mutability};
+use crate::mir::{Operand, Place, Rvalue, StatementKind, UnwindAction, VarDebugInfoContents};
+use crate::ty::{Const, IndexedVal, Ty};
+use crate::{with, Body, Mutability};
+use fmt::{Display, Formatter};
+use std::fmt::Debug;
 use std::io::Write;
-use std::{io, iter};
+use std::{fmt, io, iter};
 
 use super::{AssertMessage, BinOp, TerminatorKind};
 
-pub fn function_name(item: CrateItem) -> String {
-    let mut pretty_name = String::new();
-    let body = item.body();
-    pretty_name.push_str("fn ");
-    pretty_name.push_str(item.name().as_str());
-    if body.arg_locals().is_empty() {
-        pretty_name.push_str("()");
-    } else {
-        pretty_name.push_str("(");
-    }
-    body.arg_locals().iter().enumerate().for_each(|(index, local)| {
-        pretty_name.push_str(format!("_{}: ", index).as_str());
-        pretty_name.push_str(&pretty_ty(local.ty.kind()));
-    });
-    if !body.arg_locals().is_empty() {
-        pretty_name.push_str(")");
+use super::BorrowKind;
+
+impl Display for Ty {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        with(|ctx| write!(f, "{}", ctx.ty_pretty(*self)))
     }
-    let return_local = body.ret_local();
-    pretty_name.push_str(" -> ");
-    pretty_name.push_str(&pretty_ty(return_local.ty.kind()));
-    pretty_name.push_str(" {");
-    pretty_name
 }
 
-pub fn function_body(body: &Body) -> String {
-    let mut pretty_body = String::new();
-    body.inner_locals().iter().enumerate().for_each(|(index, local)| {
-        pretty_body.push_str("    ");
-        pretty_body.push_str(format!("let {}", ret_mutability(&local.mutability)).as_str());
-        pretty_body.push_str(format!("_{}: ", index).as_str());
-        pretty_body.push_str(format!("{}", pretty_ty(local.ty.kind())).as_str());
-        pretty_body.push_str(";\n");
-    });
-    pretty_body.push_str("}");
-    pretty_body
+impl Debug for Place {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        with(|ctx| write!(f, "{}", ctx.place_pretty(self)))
+    }
 }
 
-pub fn ret_mutability(mutability: &Mutability) -> String {
-    match mutability {
-        Mutability::Not => "".to_string(),
-        Mutability::Mut => "mut ".to_string(),
-    }
+pub(crate) fn function_body<W: Write>(writer: &mut W, body: &Body, name: &str) -> io::Result<()> {
+    write!(writer, "fn {}(", name)?;
+    body.arg_locals()
+        .iter()
+        .enumerate()
+        .try_for_each(|(index, local)| write!(writer, "_{}: {}", index + 1, local.ty))?;
+    write!(writer, ")")?;
+
+    let return_local = body.ret_local();
+    writeln!(writer, " -> {} {{", return_local.ty)?;
+
+    body.locals().iter().enumerate().try_for_each(|(index, local)| -> io::Result<()> {
+        if index == 0 || index > body.arg_count {
+            writeln!(writer, "    let {}_{}: {};", pretty_mut(local.mutability), index, local.ty)
+        } else {
+            Ok(())
+        }
+    })?;
+
+    body.var_debug_info.iter().try_for_each(|info| {
+        let content = match &info.value {
+            VarDebugInfoContents::Place(place) => {
+                format!("{place:?}")
+            }
+            VarDebugInfoContents::Const(constant) => pretty_const(&constant.const_),
+        };
+        writeln!(writer, "    debug {} => {};", info.name, content)
+    })?;
+
+    body.blocks
+        .iter()
+        .enumerate()
+        .map(|(index, block)| -> io::Result<()> {
+            writeln!(writer, "    bb{}: {{", index)?;
+            let _ = block
+                .statements
+                .iter()
+                .map(|statement| -> io::Result<()> {
+                    pretty_statement(writer, &statement.kind)?;
+                    Ok(())
+                })
+                .collect::<Vec<_>>();
+            pretty_terminator(writer, &block.terminator.kind)?;
+            writeln!(writer, "    }}").unwrap();
+            Ok(())
+        })
+        .collect::<Result<Vec<_>, _>>()?;
+    writeln!(writer, "}}")?;
+    Ok(())
 }
 
-pub fn pretty_statement(statement: &StatementKind) -> String {
-    let mut pretty = String::new();
+fn pretty_statement<W: Write>(writer: &mut W, statement: &StatementKind) -> io::Result<()> {
     match statement {
         StatementKind::Assign(place, rval) => {
-            pretty.push_str(format!("        _{} = ", place.local).as_str());
-            pretty.push_str(format!("{}", &pretty_rvalue(rval)).as_str());
+            write!(writer, "        {:?} = ", place)?;
+            pretty_rvalue(writer, rval)?;
+            writeln!(writer, ";")
         }
         // FIXME: Add rest of the statements
-        StatementKind::FakeRead(_, _) => {
-            return String::from("StatementKind::FakeRead:Unimplemented");
+        StatementKind::FakeRead(cause, place) => {
+            writeln!(writer, "FakeRead({cause:?}, {place:?});")
         }
-        StatementKind::SetDiscriminant { .. } => {
-            return String::from("StatementKind::SetDiscriminant:Unimplemented");
+        StatementKind::SetDiscriminant { place, variant_index } => {
+            writeln!(writer, "discriminant({place:?} = {};", variant_index.to_index())
         }
-        StatementKind::Deinit(_) => return String::from("StatementKind::Deinit:Unimplemented"),
-        StatementKind::StorageLive(_) => {
-            return String::from("StatementKind::StorageLive:Unimplemented");
+        StatementKind::Deinit(place) => writeln!(writer, "Deinit({place:?};"),
+        StatementKind::StorageLive(local) => {
+            writeln!(writer, "StorageLive(_{local});")
         }
-        StatementKind::StorageDead(_) => {
-            return String::from("StatementKind::StorageDead:Unimplemented");
+        StatementKind::StorageDead(local) => {
+            writeln!(writer, "StorageDead(_{local});")
         }
-        StatementKind::Retag(_, _) => return String::from("StatementKind::Retag:Unimplemented"),
-        StatementKind::PlaceMention(_) => {
-            return String::from("StatementKind::PlaceMention:Unimplemented");
-        }
-        StatementKind::AscribeUserType { .. } => {
-            return String::from("StatementKind::AscribeUserType:Unimplemented");
-        }
-        StatementKind::Coverage(_) => return String::from("StatementKind::Coverage:Unimplemented"),
-        StatementKind::Intrinsic(_) => {
-            return String::from("StatementKind::Intrinsic:Unimplemented");
+        StatementKind::Retag(kind, place) => writeln!(writer, "Retag({kind:?}, {place:?});"),
+        StatementKind::PlaceMention(place) => {
+            writeln!(writer, "PlaceMention({place:?};")
         }
         StatementKind::ConstEvalCounter => {
-            return String::from("StatementKind::ConstEvalCounter:Unimplemented");
+            writeln!(writer, "ConstEvalCounter;")
+        }
+        StatementKind::Nop => writeln!(writer, "nop;"),
+        StatementKind::AscribeUserType { .. }
+        | StatementKind::Coverage(_)
+        | StatementKind::Intrinsic(_) => {
+            // FIX-ME: Make them pretty.
+            writeln!(writer, "{statement:?};")
         }
-        StatementKind::Nop => return String::from("StatementKind::Nop:Unimplemented"),
     }
-    pretty
 }
 
-pub fn pretty_terminator<W: io::Write>(terminator: &TerminatorKind, w: &mut W) -> io::Result<()> {
-    write!(w, "{}", pretty_terminator_head(terminator))?;
+fn pretty_terminator<W: Write>(writer: &mut W, terminator: &TerminatorKind) -> io::Result<()> {
+    pretty_terminator_head(writer, terminator)?;
     let successors = terminator.successors();
     let successor_count = successors.len();
     let labels = pretty_successor_labels(terminator);
 
     let show_unwind = !matches!(terminator.unwind(), None | Some(UnwindAction::Cleanup(_)));
-    let fmt_unwind = |fmt: &mut dyn Write| -> io::Result<()> {
-        write!(fmt, "unwind ")?;
+    let fmt_unwind = |w: &mut W| -> io::Result<()> {
+        write!(w, "unwind ")?;
         match terminator.unwind() {
             None | Some(UnwindAction::Cleanup(_)) => unreachable!(),
-            Some(UnwindAction::Continue) => write!(fmt, "continue"),
-            Some(UnwindAction::Unreachable) => write!(fmt, "unreachable"),
-            Some(UnwindAction::Terminate) => write!(fmt, "terminate"),
+            Some(UnwindAction::Continue) => write!(w, "continue"),
+            Some(UnwindAction::Unreachable) => write!(w, "unreachable"),
+            Some(UnwindAction::Terminate) => write!(w, "terminate"),
         }
     };
 
     match (successor_count, show_unwind) {
-        (0, false) => Ok(()),
+        (0, false) => {}
         (0, true) => {
-            write!(w, " -> ")?;
-            fmt_unwind(w)?;
-            Ok(())
-        }
-        (1, false) => {
-            write!(w, " -> {:?}", successors[0])?;
-            Ok(())
+            write!(writer, " -> ")?;
+            fmt_unwind(writer)?;
         }
+        (1, false) => write!(writer, " -> bb{:?}", successors[0])?,
         _ => {
-            write!(w, " -> [")?;
+            write!(writer, " -> [")?;
             for (i, target) in successors.iter().enumerate() {
                 if i > 0 {
-                    write!(w, ", ")?;
+                    write!(writer, ", ")?;
                 }
-                write!(w, "{}: bb{:?}", labels[i], target)?;
+                write!(writer, "{}: bb{:?}", labels[i], target)?;
             }
             if show_unwind {
-                write!(w, ", ")?;
-                fmt_unwind(w)?;
+                write!(writer, ", ")?;
+                fmt_unwind(writer)?;
             }
-            write!(w, "]")
+            write!(writer, "]")?;
         }
-    }?;
+    };
 
-    Ok(())
+    writeln!(writer, ";")
 }
 
-pub fn pretty_terminator_head(terminator: &TerminatorKind) -> String {
+fn pretty_terminator_head<W: Write>(writer: &mut W, terminator: &TerminatorKind) -> io::Result<()> {
     use self::TerminatorKind::*;
-    let mut pretty = String::new();
+    const INDENT: &'static str = "        ";
     match terminator {
-        Goto { .. } => format!("        goto"),
+        Goto { .. } => write!(writer, "{INDENT}goto"),
         SwitchInt { discr, .. } => {
-            format!("        switchInt(_{})", pretty_operand(discr))
+            write!(writer, "{INDENT}switchInt({})", pretty_operand(discr))
         }
-        Resume => format!("        resume"),
-        Abort => format!("        abort"),
-        Return => format!("        return"),
-        Unreachable => format!("        unreachable"),
-        Drop { place, .. } => format!("        drop(_{:?})", place.local),
+        Resume => write!(writer, "{INDENT}resume"),
+        Abort => write!(writer, "{INDENT}abort"),
+        Return => write!(writer, "{INDENT}return"),
+        Unreachable => write!(writer, "{INDENT}unreachable"),
+        Drop { place, .. } => write!(writer, "{INDENT}drop({:?})", place),
         Call { func, args, destination, .. } => {
-            pretty.push_str("        ");
-            pretty.push_str(format!("_{} = ", destination.local).as_str());
-            pretty.push_str(&pretty_operand(func));
-            pretty.push_str("(");
-            args.iter().enumerate().for_each(|(i, arg)| {
-                if i > 0 {
-                    pretty.push_str(", ");
-                }
-                pretty.push_str(&pretty_operand(arg));
-            });
-            pretty.push_str(")");
-            pretty
+            write!(writer, "{INDENT}{:?} = {}(", destination, pretty_operand(func))?;
+            let mut args_iter = args.iter();
+            args_iter.next().map_or(Ok(()), |arg| write!(writer, "{}", pretty_operand(arg)))?;
+            args_iter.try_for_each(|arg| write!(writer, ", {}", pretty_operand(arg)))?;
+            write!(writer, ")")
         }
         Assert { cond, expected, msg, target: _, unwind: _ } => {
-            pretty.push_str("        assert(");
+            write!(writer, "{INDENT}assert(")?;
             if !expected {
-                pretty.push_str("!");
+                write!(writer, "!")?;
             }
-            pretty.push_str(format!("{} bool),", &pretty_operand(cond)).as_str());
-            pretty.push_str(&pretty_assert_message(msg));
-            pretty.push_str(")");
-            pretty
+            write!(writer, "{}, ", &pretty_operand(cond))?;
+            pretty_assert_message(writer, msg)?;
+            write!(writer, ")")
         }
-        InlineAsm { .. } => todo!(),
+        InlineAsm { .. } => write!(writer, "{INDENT}InlineAsm"),
     }
 }
 
-pub fn pretty_successor_labels(terminator: &TerminatorKind) -> Vec<String> {
+fn pretty_successor_labels(terminator: &TerminatorKind) -> Vec<String> {
     use self::TerminatorKind::*;
     match terminator {
         Resume | Abort | Return | Unreachable => vec![],
@@ -201,283 +209,174 @@ pub fn pretty_successor_labels(terminator: &TerminatorKind) -> Vec<String> {
             vec!["success".into(), "unwind".into()]
         }
         Assert { unwind: _, .. } => vec!["success".into()],
-        InlineAsm { .. } => todo!(),
+        InlineAsm { destination: Some(_), .. } => vec!["goto".into(), "unwind".into()],
+        InlineAsm { destination: None, .. } => vec!["unwind".into()],
     }
 }
 
-pub fn pretty_assert_message(msg: &AssertMessage) -> String {
-    let mut pretty = String::new();
+fn pretty_assert_message<W: Write>(writer: &mut W, msg: &AssertMessage) -> io::Result<()> {
     match msg {
         AssertMessage::BoundsCheck { len, index } => {
             let pretty_len = pretty_operand(len);
             let pretty_index = pretty_operand(index);
-            pretty.push_str(format!("\"index out of bounds: the length is {{}} but the index is {{}}\", {pretty_len}, {pretty_index}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"index out of bounds: the length is {{}} but the index is {{}}\", {pretty_len}, {pretty_index}"
+            )
         }
         AssertMessage::Overflow(BinOp::Add, l, r) => {
             let pretty_l = pretty_operand(l);
             let pretty_r = pretty_operand(r);
-            pretty.push_str(format!("\"attempt to compute `{{}} + {{}}`, which would overflow\", {pretty_l}, {pretty_r}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"attempt to compute `{{}} + {{}}`, which would overflow\", {pretty_l}, {pretty_r}"
+            )
         }
         AssertMessage::Overflow(BinOp::Sub, l, r) => {
             let pretty_l = pretty_operand(l);
             let pretty_r = pretty_operand(r);
-            pretty.push_str(format!("\"attempt to compute `{{}} - {{}}`, which would overflow\", {pretty_l}, {pretty_r}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"attempt to compute `{{}} - {{}}`, which would overflow\", {pretty_l}, {pretty_r}"
+            )
         }
         AssertMessage::Overflow(BinOp::Mul, l, r) => {
             let pretty_l = pretty_operand(l);
             let pretty_r = pretty_operand(r);
-            pretty.push_str(format!("\"attempt to compute `{{}} * {{}}`, which would overflow\", {pretty_l}, {pretty_r}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"attempt to compute `{{}} * {{}}`, which would overflow\", {pretty_l}, {pretty_r}"
+            )
         }
         AssertMessage::Overflow(BinOp::Div, l, r) => {
             let pretty_l = pretty_operand(l);
             let pretty_r = pretty_operand(r);
-            pretty.push_str(format!("\"attempt to compute `{{}} / {{}}`, which would overflow\", {pretty_l}, {pretty_r}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"attempt to compute `{{}} / {{}}`, which would overflow\", {pretty_l}, {pretty_r}"
+            )
         }
         AssertMessage::Overflow(BinOp::Rem, l, r) => {
             let pretty_l = pretty_operand(l);
             let pretty_r = pretty_operand(r);
-            pretty.push_str(format!("\"attempt to compute `{{}} % {{}}`, which would overflow\", {pretty_l}, {pretty_r}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"attempt to compute `{{}} % {{}}`, which would overflow\", {pretty_l}, {pretty_r}"
+            )
         }
         AssertMessage::Overflow(BinOp::Shr, _, r) => {
             let pretty_r = pretty_operand(r);
-            pretty.push_str(
-                format!("\"attempt to shift right by `{{}}`, which would overflow\", {pretty_r}")
-                    .as_str(),
-            );
-            pretty
+            write!(writer, "\"attempt to shift right by `{{}}`, which would overflow\", {pretty_r}")
         }
         AssertMessage::Overflow(BinOp::Shl, _, r) => {
             let pretty_r = pretty_operand(r);
-            pretty.push_str(
-                format!("\"attempt to shift left by `{{}}`, which would overflow\", {pretty_r}")
-                    .as_str(),
-            );
-            pretty
+            write!(writer, "\"attempt to shift left by `{{}}`, which would overflow\", {pretty_r}")
         }
         AssertMessage::Overflow(op, _, _) => unreachable!("`{:?}` cannot overflow", op),
         AssertMessage::OverflowNeg(op) => {
             let pretty_op = pretty_operand(op);
-            pretty.push_str(
-                format!("\"attempt to negate `{{}}`, which would overflow\", {pretty_op}").as_str(),
-            );
-            pretty
+            write!(writer, "\"attempt to negate `{{}}`, which would overflow\", {pretty_op}")
         }
         AssertMessage::DivisionByZero(op) => {
             let pretty_op = pretty_operand(op);
-            pretty.push_str(format!("\"attempt to divide `{{}}` by zero\", {pretty_op}").as_str());
-            pretty
+            write!(writer, "\"attempt to divide `{{}}` by zero\", {pretty_op}")
         }
         AssertMessage::RemainderByZero(op) => {
             let pretty_op = pretty_operand(op);
-            pretty.push_str(
-                format!("\"attempt to calculate the remainder of `{{}}` with a divisor of zero\", {pretty_op}").as_str(),
-            );
-            pretty
+            write!(
+                writer,
+                "\"attempt to calculate the remainder of `{{}}` with a divisor of zero\", {pretty_op}"
+            )
         }
         AssertMessage::MisalignedPointerDereference { required, found } => {
             let pretty_required = pretty_operand(required);
             let pretty_found = pretty_operand(found);
-            pretty.push_str(format!("\"misaligned pointer dereference: address must be a multiple of {{}} but is {{}}\",{pretty_required}, {pretty_found}").as_str());
-            pretty
+            write!(
+                writer,
+                "\"misaligned pointer dereference: address must be a multiple of {{}} but is {{}}\",{pretty_required}, {pretty_found}"
+            )
         }
         AssertMessage::ResumedAfterReturn(_) | AssertMessage::ResumedAfterPanic(_) => {
-            msg.description().unwrap().to_string()
+            write!(writer, "{}", msg.description().unwrap())
         }
     }
 }
 
-pub fn pretty_operand(operand: &Operand) -> String {
-    let mut pretty = String::new();
+fn pretty_operand(operand: &Operand) -> String {
     match operand {
         Operand::Copy(copy) => {
-            pretty.push_str("");
-            pretty.push_str(format!("{}", copy.local).as_str());
+            format!("{:?}", copy)
         }
         Operand::Move(mv) => {
-            pretty.push_str("move ");
-            pretty.push_str(format!("_{}", mv.local).as_str());
-        }
-        Operand::Constant(cnst) => {
-            pretty.push_str("const ");
-            pretty.push_str(with(|cx| cx.const_literal(&cnst.literal)).as_str());
+            format!("move {:?}", mv)
         }
+        Operand::Constant(cnst) => pretty_const(&cnst.literal),
     }
-    pretty
 }
 
-pub fn pretty_rvalue(rval: &Rvalue) -> String {
-    let mut pretty = String::new();
+fn pretty_const(literal: &Const) -> String {
+    with(|cx| cx.const_pretty(&literal))
+}
+
+fn pretty_rvalue<W: Write>(writer: &mut W, rval: &Rvalue) -> io::Result<()> {
     match rval {
-        Rvalue::AddressOf(muta, addr) => {
-            pretty.push_str("&raw ");
-            pretty.push_str(&ret_mutability(muta));
-            pretty.push_str(format!("(*_{})", addr.local).as_str());
-        }
-        Rvalue::Aggregate(aggregatekind, operands) => {
-            pretty.push_str(format!("{:#?}", aggregatekind).as_str());
-            pretty.push_str("(");
-            operands.iter().enumerate().for_each(|(i, op)| {
-                pretty.push_str(&pretty_operand(op));
-                if i != operands.len() - 1 {
-                    pretty.push_str(", ");
-                }
-            });
-            pretty.push_str(")");
+        Rvalue::AddressOf(mutability, place) => {
+            write!(writer, "&raw {}(*{:?})", &pretty_mut(*mutability), place)
         }
-        Rvalue::BinaryOp(bin, op, op2) => {
-            pretty.push_str(&pretty_operand(op));
-            pretty.push_str(" ");
-            pretty.push_str(format!("{:#?}", bin).as_str());
-            pretty.push_str(" ");
-            pretty.push_str(&pretty_operand(op2));
+        Rvalue::Aggregate(aggregate_kind, operands) => {
+            // FIXME: Add pretty_aggregate function that returns a pretty string
+            write!(writer, "{aggregate_kind:?} (")?;
+            let mut op_iter = operands.iter();
+            op_iter.next().map_or(Ok(()), |op| write!(writer, "{}", pretty_operand(op)))?;
+            op_iter.try_for_each(|op| write!(writer, ", {}", pretty_operand(op)))?;
+            write!(writer, ")")
+        }
+        Rvalue::BinaryOp(bin, op1, op2) => {
+            write!(writer, "{:?}({}, {})", bin, &pretty_operand(op1), pretty_operand(op2))
         }
         Rvalue::Cast(_, op, ty) => {
-            pretty.push_str(&pretty_operand(op));
-            pretty.push_str(" as ");
-            pretty.push_str(&pretty_ty(ty.kind()));
+            write!(writer, "{} as {}", pretty_operand(op), ty)
         }
         Rvalue::CheckedBinaryOp(bin, op1, op2) => {
-            pretty.push_str(&pretty_operand(op1));
-            pretty.push_str(" ");
-            pretty.push_str(format!("{:#?}", bin).as_str());
-            pretty.push_str(" ");
-            pretty.push_str(&pretty_operand(op2));
+            write!(writer, "Checked{:?}({}, {})", bin, &pretty_operand(op1), pretty_operand(op2))
         }
         Rvalue::CopyForDeref(deref) => {
-            pretty.push_str("CopyForDeref");
-            pretty.push_str(format!("{}", deref.local).as_str());
+            write!(writer, "CopyForDeref({:?})", deref)
         }
         Rvalue::Discriminant(place) => {
-            pretty.push_str("discriminant");
-            pretty.push_str(format!("{}", place.local).as_str());
+            write!(writer, "discriminant({:?})", place)
         }
         Rvalue::Len(len) => {
-            pretty.push_str("len");
-            pretty.push_str(format!("{}", len.local).as_str());
+            write!(writer, "len({:?})", len)
         }
         Rvalue::Ref(_, borrowkind, place) => {
-            pretty.push_str("ref");
-            pretty.push_str(format!("{:#?}", borrowkind).as_str());
-            pretty.push_str(format!("{}", place.local).as_str());
+            let kind = match borrowkind {
+                BorrowKind::Shared => "&",
+                BorrowKind::Fake => "&fake ",
+                BorrowKind::Mut { .. } => "&mut ",
+            };
+            write!(writer, "{kind}{:?}", place)
         }
         Rvalue::Repeat(op, cnst) => {
-            pretty.push_str(&pretty_operand(op));
-            pretty.push_str(" ");
-            pretty.push_str(&pretty_ty(cnst.ty().kind()));
+            write!(writer, "{} \" \" {}", &pretty_operand(op), cnst.ty())
         }
-        Rvalue::ShallowInitBox(_, _) => (),
+        Rvalue::ShallowInitBox(_, _) => Ok(()),
         Rvalue::ThreadLocalRef(item) => {
-            pretty.push_str("thread_local_ref");
-            pretty.push_str(format!("{:#?}", item).as_str());
+            write!(writer, "thread_local_ref{:?}", item)
         }
         Rvalue::NullaryOp(nul, ty) => {
-            pretty.push_str(format!("{:#?}", nul).as_str());
-            pretty.push_str(&pretty_ty(ty.kind()));
-            pretty.push_str(" ");
+            write!(writer, "{:?} {} \" \"", nul, ty)
         }
         Rvalue::UnaryOp(un, op) => {
-            pretty.push_str(&pretty_operand(op));
-            pretty.push_str(" ");
-            pretty.push_str(format!("{:#?}", un).as_str());
+            write!(writer, "{} \" \" {:?}", pretty_operand(op), un)
         }
-        Rvalue::Use(op) => pretty.push_str(&pretty_operand(op)),
+        Rvalue::Use(op) => write!(writer, "{}", pretty_operand(op)),
     }
-    pretty
 }
 
-pub fn pretty_ty(ty: TyKind) -> String {
-    let mut pretty = String::new();
-    match ty {
-        TyKind::RigidTy(rigid_ty) => match rigid_ty {
-            RigidTy::Bool => "bool".to_string(),
-            RigidTy::Char => "char".to_string(),
-            RigidTy::Int(i) => match i {
-                IntTy::Isize => "isize".to_string(),
-                IntTy::I8 => "i8".to_string(),
-                IntTy::I16 => "i16".to_string(),
-                IntTy::I32 => "i32".to_string(),
-                IntTy::I64 => "i64".to_string(),
-                IntTy::I128 => "i128".to_string(),
-            },
-            RigidTy::Uint(u) => match u {
-                UintTy::Usize => "usize".to_string(),
-                UintTy::U8 => "u8".to_string(),
-                UintTy::U16 => "u16".to_string(),
-                UintTy::U32 => "u32".to_string(),
-                UintTy::U64 => "u64".to_string(),
-                UintTy::U128 => "u128".to_string(),
-            },
-            RigidTy::Float(f) => match f {
-                FloatTy::F32 => "f32".to_string(),
-                FloatTy::F64 => "f64".to_string(),
-            },
-            RigidTy::Adt(def, _) => {
-                format!("{:#?}", with(|cx| cx.def_ty(def.0)))
-            }
-            RigidTy::Str => "str".to_string(),
-            RigidTy::Array(ty, len) => {
-                format!("[{}; {}]", pretty_ty(ty.kind()), with(|cx| cx.const_literal(&len)))
-            }
-            RigidTy::Slice(ty) => {
-                format!("[{}]", pretty_ty(ty.kind()))
-            }
-            RigidTy::RawPtr(ty, mutability) => {
-                pretty.push_str("*");
-                match mutability {
-                    Mutability::Not => pretty.push_str("const "),
-                    Mutability::Mut => pretty.push_str("mut "),
-                }
-                pretty.push_str(&pretty_ty(ty.kind()));
-                pretty
-            }
-            RigidTy::Ref(_, ty, mutability) => match mutability {
-                Mutability::Not => format!("&{}", pretty_ty(ty.kind())),
-                Mutability::Mut => format!("&mut {}", pretty_ty(ty.kind())),
-            },
-            RigidTy::FnDef(_, _) => format!("{:#?}", rigid_ty),
-            RigidTy::FnPtr(_) => format!("{:#?}", rigid_ty),
-            RigidTy::Closure(_, _) => format!("{:#?}", rigid_ty),
-            RigidTy::Coroutine(_, _, _) => format!("{:#?}", rigid_ty),
-            RigidTy::Dynamic(data, region, repr) => {
-                // FIXME: Fix binder printing, it looks ugly now
-                pretty.push_str("(");
-                match repr {
-                    DynKind::Dyn => pretty.push_str("dyn "),
-                    DynKind::DynStar => pretty.push_str("dyn* "),
-                }
-                pretty.push_str(format!("{:#?}", data).as_str());
-                pretty.push_str(format!(" +  {:#?} )", region).as_str());
-                pretty
-            }
-            RigidTy::Never => "!".to_string(),
-            RigidTy::Tuple(tuple) => {
-                if tuple.is_empty() {
-                    "()".to_string()
-                } else {
-                    let mut tuple_str = String::new();
-                    tuple_str.push_str("(");
-                    tuple.iter().enumerate().for_each(|(i, ty)| {
-                        tuple_str.push_str(&pretty_ty(ty.kind()));
-                        if i != tuple.len() - 1 {
-                            tuple_str.push_str(", ");
-                        }
-                    });
-                    tuple_str.push_str(")");
-                    tuple_str
-                }
-            }
-            _ => format!("{:#?}", rigid_ty),
-        },
-        TyKind::Alias(_, _) => format!("{:#?}", ty),
-        TyKind::Param(param_ty) => {
-            format!("{:#?}", param_ty.name)
-        }
-        TyKind::Bound(_, _) => format!("{:#?}", ty),
+fn pretty_mut(mutability: Mutability) -> &'static str {
+    match mutability {
+        Mutability::Not => " ",
+        Mutability::Mut => "mut ",
     }
 }
diff --git a/config.example.toml b/config.example.toml
index f94553dd63f..b8cdc2ec848 100644
--- a/config.example.toml
+++ b/config.example.toml
@@ -915,6 +915,6 @@
 # Available options: fast, balanced, best
 #compression-profile = "fast"
 
-# Copy the linker, DLLs, and various libraries from MinGW into the rustc toolchain.
+# Copy the linker, DLLs, and various libraries from MinGW into the Rust toolchain.
 # Only applies when the host or target is pc-windows-gnu.
 #include-mingw-linker = true
diff --git a/library/alloc/src/collections/btree/map.rs b/library/alloc/src/collections/btree/map.rs
index e99c6220e20..3875f61efaf 100644
--- a/library/alloc/src/collections/btree/map.rs
+++ b/library/alloc/src/collections/btree/map.rs
@@ -72,7 +72,7 @@ pub(super) const MIN_LEN: usize = node::MIN_LEN_AFTER_SPLIT;
 /// `BTreeMap` that observed the logic error and not result in undefined behavior. This could
 /// include panics, incorrect results, aborts, memory leaks, and non-termination.
 ///
-/// Iterators obtained from functions such as [`BTreeMap::iter`], [`BTreeMap::values`], or
+/// Iterators obtained from functions such as [`BTreeMap::iter`], [`BTreeMap::into_iter`], [`BTreeMap::values`], or
 /// [`BTreeMap::keys`] produce their items in order by key, and take worst-case logarithmic and
 /// amortized constant time per item returned.
 ///
@@ -415,7 +415,7 @@ impl<'a, K: 'a, V: 'a> Default for IterMut<'a, K, V> {
     }
 }
 
-/// An owning iterator over the entries of a `BTreeMap`.
+/// An owning iterator over the entries of a `BTreeMap`, sorted by key.
 ///
 /// This `struct` is created by the [`into_iter`] method on [`BTreeMap`]
 /// (provided by the [`IntoIterator`] trait). See its documentation for more.
@@ -1637,6 +1637,7 @@ impl<K, V, A: Allocator + Clone> IntoIterator for BTreeMap<K, V, A> {
     type Item = (K, V);
     type IntoIter = IntoIter<K, V, A>;
 
+    /// Gets an owning iterator over the entries of the map, sorted by key.
     fn into_iter(self) -> IntoIter<K, V, A> {
         let mut me = ManuallyDrop::new(self);
         if let Some(root) = me.root.take() {
diff --git a/library/alloc/src/collections/btree/set.rs b/library/alloc/src/collections/btree/set.rs
index ed91ae1a66e..7508ae468ae 100644
--- a/library/alloc/src/collections/btree/set.rs
+++ b/library/alloc/src/collections/btree/set.rs
@@ -27,7 +27,7 @@ use crate::alloc::{Allocator, Global};
 /// `BTreeSet` that observed the logic error and not result in undefined behavior. This could
 /// include panics, incorrect results, aborts, memory leaks, and non-termination.
 ///
-/// Iterators returned by [`BTreeSet::iter`] produce their items in order, and take worst-case
+/// Iterators returned by [`BTreeSet::iter`] and [`BTreeSet::into_iter`] produce their items in order, and take worst-case
 /// logarithmic and amortized constant time per item returned.
 ///
 /// [`Cell`]: core::cell::Cell
@@ -140,7 +140,7 @@ impl<T: fmt::Debug> fmt::Debug for Iter<'_, T> {
     }
 }
 
-/// An owning iterator over the items of a `BTreeSet`.
+/// An owning iterator over the items of a `BTreeSet` in ascending order.
 ///
 /// This `struct` is created by the [`into_iter`] method on [`BTreeSet`]
 /// (provided by the [`IntoIterator`] trait). See its documentation for more.
@@ -1237,7 +1237,7 @@ impl<T, A: Allocator + Clone> IntoIterator for BTreeSet<T, A> {
     type Item = T;
     type IntoIter = IntoIter<T, A>;
 
-    /// Gets an iterator for moving out the `BTreeSet`'s contents.
+    /// Gets an iterator for moving out the `BTreeSet`'s contents in ascending order.
     ///
     /// # Examples
     ///
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 80f0f2acc99..7e3e2fb38b1 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -233,7 +233,7 @@ macro_rules! acquire {
 ///     let val = Arc::clone(&val);
 ///
 ///     thread::spawn(move || {
-///         let v = val.fetch_add(1, Ordering::SeqCst);
+///         let v = val.fetch_add(1, Ordering::Relaxed);
 ///         println!("{v:?}");
 ///     });
 /// }
diff --git a/library/alloc/src/vec/in_place_collect.rs b/library/alloc/src/vec/in_place_collect.rs
index 07eb91c9005..4907a45e881 100644
--- a/library/alloc/src/vec/in_place_collect.rs
+++ b/library/alloc/src/vec/in_place_collect.rs
@@ -229,96 +229,106 @@ where
     I: Iterator<Item = T> + InPlaceCollect,
     <I as SourceIter>::Source: AsVecIntoIter,
 {
-    default fn from_iter(mut iterator: I) -> Self {
-        // See "Layout constraints" section in the module documentation. We rely on const
-        // optimization here since these conditions currently cannot be expressed as trait bounds
-        if const { !in_place_collectible::<T, I::Src>(I::MERGE_BY, I::EXPAND_BY) } {
-            // fallback to more generic implementations
-            return SpecFromIterNested::from_iter(iterator);
-        }
-
-        let (src_buf, src_ptr, src_cap, mut dst_buf, dst_end, dst_cap) = unsafe {
-            let inner = iterator.as_inner().as_into_iter();
-            (
-                inner.buf.as_ptr(),
-                inner.ptr,
-                inner.cap,
-                inner.buf.as_ptr() as *mut T,
-                inner.end as *const T,
-                inner.cap * mem::size_of::<I::Src>() / mem::size_of::<T>(),
-            )
+    default fn from_iter(iterator: I) -> Self {
+        // Select the implementation in const eval to avoid codegen of the dead branch to improve compile times.
+        let fun: fn(I) -> Vec<T> = const {
+            // See "Layout constraints" section in the module documentation. We use const conditions here
+            // since these conditions currently cannot be expressed as trait bounds
+            if in_place_collectible::<T, I::Src>(I::MERGE_BY, I::EXPAND_BY) {
+                from_iter_in_place
+            } else {
+                // fallback
+                SpecFromIterNested::<T, I>::from_iter
+            }
         };
 
-        // SAFETY: `dst_buf` and `dst_end` are the start and end of the buffer.
-        let len = unsafe { SpecInPlaceCollect::collect_in_place(&mut iterator, dst_buf, dst_end) };
+        fun(iterator)
+    }
+}
 
-        let src = unsafe { iterator.as_inner().as_into_iter() };
-        // check if SourceIter contract was upheld
-        // caveat: if they weren't we might not even make it to this point
-        debug_assert_eq!(src_buf, src.buf.as_ptr());
-        // check InPlaceIterable contract. This is only possible if the iterator advanced the
-        // source pointer at all. If it uses unchecked access via TrustedRandomAccess
-        // then the source pointer will stay in its initial position and we can't use it as reference
-        if src.ptr != src_ptr {
-            debug_assert!(
-                unsafe { dst_buf.add(len) as *const _ } <= src.ptr.as_ptr(),
-                "InPlaceIterable contract violation, write pointer advanced beyond read pointer"
-            );
-        }
+fn from_iter_in_place<I, T>(mut iterator: I) -> Vec<T>
+where
+    I: Iterator<Item = T> + InPlaceCollect,
+    <I as SourceIter>::Source: AsVecIntoIter,
+{
+    let (src_buf, src_ptr, src_cap, mut dst_buf, dst_end, dst_cap) = unsafe {
+        let inner = iterator.as_inner().as_into_iter();
+        (
+            inner.buf.as_ptr(),
+            inner.ptr,
+            inner.cap,
+            inner.buf.as_ptr() as *mut T,
+            inner.end as *const T,
+            inner.cap * mem::size_of::<I::Src>() / mem::size_of::<T>(),
+        )
+    };
 
-        // The ownership of the source allocation and the new `T` values is temporarily moved into `dst_guard`.
-        // This is safe because
-        // * `forget_allocation_drop_remaining` immediately forgets the allocation
-        // before any panic can occur in order to avoid any double free, and then proceeds to drop
-        // any remaining values at the tail of the source.
-        // * the shrink either panics without invalidating the allocation, aborts or
-        //   succeeds. In the last case we disarm the guard.
-        //
-        // Note: This access to the source wouldn't be allowed by the TrustedRandomIteratorNoCoerce
-        // contract (used by SpecInPlaceCollect below). But see the "O(1) collect" section in the
-        // module documentation why this is ok anyway.
-        let dst_guard =
-            InPlaceDstDataSrcBufDrop { ptr: dst_buf, len, src_cap, src: PhantomData::<I::Src> };
-        src.forget_allocation_drop_remaining();
+    // SAFETY: `dst_buf` and `dst_end` are the start and end of the buffer.
+    let len = unsafe { SpecInPlaceCollect::collect_in_place(&mut iterator, dst_buf, dst_end) };
 
-        // Adjust the allocation if the source had a capacity in bytes that wasn't a multiple
-        // of the destination type size.
-        // Since the discrepancy should generally be small this should only result in some
-        // bookkeeping updates and no memmove.
-        if needs_realloc::<I::Src, T>(src_cap, dst_cap) {
-            let alloc = Global;
-            debug_assert_ne!(src_cap, 0);
-            debug_assert_ne!(dst_cap, 0);
-            unsafe {
-                // The old allocation exists, therefore it must have a valid layout.
-                let src_align = mem::align_of::<I::Src>();
-                let src_size = mem::size_of::<I::Src>().unchecked_mul(src_cap);
-                let old_layout = Layout::from_size_align_unchecked(src_size, src_align);
+    let src = unsafe { iterator.as_inner().as_into_iter() };
+    // check if SourceIter contract was upheld
+    // caveat: if they weren't we might not even make it to this point
+    debug_assert_eq!(src_buf, src.buf.as_ptr());
+    // check InPlaceIterable contract. This is only possible if the iterator advanced the
+    // source pointer at all. If it uses unchecked access via TrustedRandomAccess
+    // then the source pointer will stay in its initial position and we can't use it as reference
+    if src.ptr != src_ptr {
+        debug_assert!(
+            unsafe { dst_buf.add(len) as *const _ } <= src.ptr.as_ptr(),
+            "InPlaceIterable contract violation, write pointer advanced beyond read pointer"
+        );
+    }
 
-                // The allocation must be equal or smaller for in-place iteration to be possible
-                // therefore the new layout must be ≤ the old one and therefore valid.
-                let dst_align = mem::align_of::<T>();
-                let dst_size = mem::size_of::<T>().unchecked_mul(dst_cap);
-                let new_layout = Layout::from_size_align_unchecked(dst_size, dst_align);
+    // The ownership of the source allocation and the new `T` values is temporarily moved into `dst_guard`.
+    // This is safe because
+    // * `forget_allocation_drop_remaining` immediately forgets the allocation
+    // before any panic can occur in order to avoid any double free, and then proceeds to drop
+    // any remaining values at the tail of the source.
+    // * the shrink either panics without invalidating the allocation, aborts or
+    //   succeeds. In the last case we disarm the guard.
+    //
+    // Note: This access to the source wouldn't be allowed by the TrustedRandomIteratorNoCoerce
+    // contract (used by SpecInPlaceCollect below). But see the "O(1) collect" section in the
+    // module documentation why this is ok anyway.
+    let dst_guard =
+        InPlaceDstDataSrcBufDrop { ptr: dst_buf, len, src_cap, src: PhantomData::<I::Src> };
+    src.forget_allocation_drop_remaining();
 
-                let result = alloc.shrink(
-                    NonNull::new_unchecked(dst_buf as *mut u8),
-                    old_layout,
-                    new_layout,
-                );
-                let Ok(reallocated) = result else { handle_alloc_error(new_layout) };
-                dst_buf = reallocated.as_ptr() as *mut T;
-            }
-        } else {
-            debug_assert_eq!(src_cap * mem::size_of::<I::Src>(), dst_cap * mem::size_of::<T>());
+    // Adjust the allocation if the source had a capacity in bytes that wasn't a multiple
+    // of the destination type size.
+    // Since the discrepancy should generally be small this should only result in some
+    // bookkeeping updates and no memmove.
+    if needs_realloc::<I::Src, T>(src_cap, dst_cap) {
+        let alloc = Global;
+        debug_assert_ne!(src_cap, 0);
+        debug_assert_ne!(dst_cap, 0);
+        unsafe {
+            // The old allocation exists, therefore it must have a valid layout.
+            let src_align = mem::align_of::<I::Src>();
+            let src_size = mem::size_of::<I::Src>().unchecked_mul(src_cap);
+            let old_layout = Layout::from_size_align_unchecked(src_size, src_align);
+
+            // The allocation must be equal or smaller for in-place iteration to be possible
+            // therefore the new layout must be ≤ the old one and therefore valid.
+            let dst_align = mem::align_of::<T>();
+            let dst_size = mem::size_of::<T>().unchecked_mul(dst_cap);
+            let new_layout = Layout::from_size_align_unchecked(dst_size, dst_align);
+
+            let result =
+                alloc.shrink(NonNull::new_unchecked(dst_buf as *mut u8), old_layout, new_layout);
+            let Ok(reallocated) = result else { handle_alloc_error(new_layout) };
+            dst_buf = reallocated.as_ptr() as *mut T;
         }
+    } else {
+        debug_assert_eq!(src_cap * mem::size_of::<I::Src>(), dst_cap * mem::size_of::<T>());
+    }
 
-        mem::forget(dst_guard);
+    mem::forget(dst_guard);
 
-        let vec = unsafe { Vec::from_raw_parts(dst_buf, len, dst_cap) };
+    let vec = unsafe { Vec::from_raw_parts(dst_buf, len, dst_cap) };
 
-        vec
-    }
+    vec
 }
 
 fn write_in_place_with_drop<T>(
diff --git a/library/alloc/src/vec/mod.rs b/library/alloc/src/vec/mod.rs
index db56b8d07c7..94bed825bb2 100644
--- a/library/alloc/src/vec/mod.rs
+++ b/library/alloc/src/vec/mod.rs
@@ -1541,6 +1541,9 @@ impl<T, A: Allocator> Vec<T, A> {
         }
 
         let len = self.len();
+        if index > len {
+            assert_failed(index, len);
+        }
 
         // space for the new element
         if len == self.buf.capacity() {
@@ -1556,10 +1559,6 @@ impl<T, A: Allocator> Vec<T, A> {
                     // Shift everything over to make space. (Duplicating the
                     // `index`th element into two consecutive places.)
                     ptr::copy(p, p.add(1), len - index);
-                } else if index == len {
-                    // No elements need shifting.
-                } else {
-                    assert_failed(index, len);
                 }
                 // Write it in, overwriting the first copy of the `index`th
                 // element.
diff --git a/library/alloc/tests/vec.rs b/library/alloc/tests/vec.rs
index aa95b4e9770..f1f841fe190 100644
--- a/library/alloc/tests/vec.rs
+++ b/library/alloc/tests/vec.rs
@@ -2643,3 +2643,44 @@ fn test_vec_from_array_ref() {
 fn test_vec_from_array_mut_ref() {
     assert_eq!(Vec::from(&mut [1, 2, 3]), vec![1, 2, 3]);
 }
+
+/// This assortment of tests, in combination with miri, verifies we handle UB on fishy arguments
+/// in the stdlib. Draining and extending the allocation are fairly well-tested earlier, but
+/// `vec.insert(usize::MAX, val)` once slipped by!
+///
+/// All code that manipulates the collection types should be tested with "trivially wrong" args.
+#[test]
+fn max_dont_panic() {
+    let mut v = vec![0];
+    let _ = v.get(usize::MAX);
+    v.shrink_to(usize::MAX);
+    v.truncate(usize::MAX);
+}
+
+#[test]
+#[should_panic]
+fn max_insert() {
+    let mut v = vec![0];
+    v.insert(usize::MAX, 1);
+}
+
+#[test]
+#[should_panic]
+fn max_remove() {
+    let mut v = vec![0];
+    v.remove(usize::MAX);
+}
+
+#[test]
+#[should_panic]
+fn max_splice() {
+    let mut v = vec![0];
+    v.splice(usize::MAX.., core::iter::once(1));
+}
+
+#[test]
+#[should_panic]
+fn max_swap_remove() {
+    let mut v = vec![0];
+    v.swap_remove(usize::MAX);
+}
diff --git a/library/core/src/alloc/global.rs b/library/core/src/alloc/global.rs
index a1fff6707bd..8df3ace54ff 100644
--- a/library/core/src/alloc/global.rs
+++ b/library/core/src/alloc/global.rs
@@ -24,10 +24,7 @@ use crate::ptr;
 /// use std::alloc::{GlobalAlloc, Layout};
 /// use std::cell::UnsafeCell;
 /// use std::ptr::null_mut;
-/// use std::sync::atomic::{
-///     AtomicUsize,
-///     Ordering::{Acquire, SeqCst},
-/// };
+/// use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
 ///
 /// const ARENA_SIZE: usize = 128 * 1024;
 /// const MAX_SUPPORTED_ALIGN: usize = 4096;
@@ -61,7 +58,7 @@ use crate::ptr;
 ///         let mut allocated = 0;
 ///         if self
 ///             .remaining
-///             .fetch_update(SeqCst, SeqCst, |mut remaining| {
+///             .fetch_update(Relaxed, Relaxed, |mut remaining| {
 ///                 if size > remaining {
 ///                     return None;
 ///                 }
@@ -81,7 +78,7 @@ use crate::ptr;
 ///
 /// fn main() {
 ///     let _s = format!("allocating a string!");
-///     let currently = ALLOCATOR.remaining.load(Acquire);
+///     let currently = ALLOCATOR.remaining.load(Relaxed);
 ///     println!("allocated so far: {}", ARENA_SIZE - currently);
 /// }
 /// ```
diff --git a/library/core/src/iter/traits/marker.rs b/library/core/src/iter/traits/marker.rs
index 8bdbca120d7..ad4d63d83b5 100644
--- a/library/core/src/iter/traits/marker.rs
+++ b/library/core/src/iter/traits/marker.rs
@@ -28,6 +28,7 @@ pub unsafe trait TrustedFused {}
 #[rustc_unsafe_specialization_marker]
 // FIXME: this should be a #[marker] and have another blanket impl for T: TrustedFused
 // but that ICEs iter::Fuse specializations.
+#[cfg_attr(not(bootstrap), lang = "fused_iterator")]
 pub trait FusedIterator: Iterator {}
 
 #[stable(feature = "fused", since = "1.26.0")]
diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs
index 0ee7e190e3d..a78842c8f8d 100644
--- a/library/core/src/macros/mod.rs
+++ b/library/core/src/macros/mod.rs
@@ -1704,14 +1704,26 @@ pub(crate) mod builtin {
     }
 
     /// Unstable placeholder for type ascription.
-    #[rustc_builtin_macro]
+    #[allow_internal_unstable(builtin_syntax)]
     #[unstable(
         feature = "type_ascription",
         issue = "23416",
         reason = "placeholder syntax for type ascription"
     )]
     pub macro type_ascribe($expr:expr, $ty:ty) {
-        /* compiler built-in */
+        builtin # type_ascribe($expr, $ty)
+    }
+
+    #[cfg(not(bootstrap))]
+    /// Unstable placeholder for deref patterns.
+    #[allow_internal_unstable(builtin_syntax)]
+    #[unstable(
+        feature = "deref_patterns",
+        issue = "87121",
+        reason = "placeholder syntax for deref patterns"
+    )]
+    pub macro deref($pat:pat) {
+        builtin # deref($pat)
     }
 
     /// Unstable implementation detail of the `rustc` compiler, do not use.
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 5027e326a9d..0083d15efae 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -558,17 +558,16 @@ use crate::panicking::{panic, panic_str};
 use crate::pin::Pin;
 use crate::{
     cmp, convert, hint, mem,
-    num::NonZero,
     ops::{self, ControlFlow, Deref, DerefMut},
     slice,
 };
 
 /// The `Option` type. See [the module level documentation](self) for more.
-#[derive(Copy, PartialOrd, Eq, Ord, Debug, Hash)]
+#[derive(Copy, Eq, Debug, Hash)]
 #[rustc_diagnostic_item = "Option"]
 #[lang = "Option"]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[allow(clippy::derived_hash_with_manual_eq)] // PartialEq is specialized
+#[allow(clippy::derived_hash_with_manual_eq)] // PartialEq is manually implemented equivalently
 pub enum Option<T> {
     /// No value.
     #[lang = "None"]
@@ -2146,83 +2145,52 @@ impl<'a, T> From<&'a mut Option<T>> for Option<&'a mut T> {
     }
 }
 
+// Ideally, LLVM should be able to optimize our derive code to this.
+// Once https://github.com/llvm/llvm-project/issues/52622 is fixed, we can
+// go back to deriving `PartialEq`.
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T> crate::marker::StructuralPartialEq for Option<T> {}
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: PartialEq> PartialEq for Option<T> {
     #[inline]
     fn eq(&self, other: &Self) -> bool {
-        SpecOptionPartialEq::eq(self, other)
-    }
-}
-
-/// This specialization trait is a workaround for LLVM not currently (2023-01)
-/// being able to optimize this itself, even though Alive confirms that it would
-/// be legal to do so: <https://github.com/llvm/llvm-project/issues/52622>
-///
-/// Once that's fixed, `Option` should go back to deriving `PartialEq`, as
-/// it used to do before <https://github.com/rust-lang/rust/pull/103556>.
-#[unstable(feature = "spec_option_partial_eq", issue = "none", reason = "exposed only for rustc")]
-#[doc(hidden)]
-pub trait SpecOptionPartialEq: Sized {
-    fn eq(l: &Option<Self>, other: &Option<Self>) -> bool;
-}
-
-#[unstable(feature = "spec_option_partial_eq", issue = "none", reason = "exposed only for rustc")]
-impl<T: PartialEq> SpecOptionPartialEq for T {
-    #[inline]
-    default fn eq(l: &Option<T>, r: &Option<T>) -> bool {
-        match (l, r) {
+        // Spelling out the cases explicitly optimizes better than
+        // `_ => false`
+        match (self, other) {
             (Some(l), Some(r)) => *l == *r,
+            (Some(_), None) => false,
+            (None, Some(_)) => false,
             (None, None) => true,
-            _ => false,
         }
     }
 }
 
-macro_rules! non_zero_option {
-    ( $( #[$stability: meta] $NZ:ty; )+ ) => {
-        $(
-            #[$stability]
-            impl SpecOptionPartialEq for $NZ {
-                #[inline]
-                fn eq(l: &Option<Self>, r: &Option<Self>) -> bool {
-                    l.map(Self::get).unwrap_or(0) == r.map(Self::get).unwrap_or(0)
-                }
-            }
-        )+
-    };
-}
-
-non_zero_option! {
-    #[stable(feature = "nonzero", since = "1.28.0")] NonZero<u8>;
-    #[stable(feature = "nonzero", since = "1.28.0")] NonZero<u16>;
-    #[stable(feature = "nonzero", since = "1.28.0")] NonZero<u32>;
-    #[stable(feature = "nonzero", since = "1.28.0")] NonZero<u64>;
-    #[stable(feature = "nonzero", since = "1.28.0")] NonZero<u128>;
-    #[stable(feature = "nonzero", since = "1.28.0")] NonZero<usize>;
-    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZero<i8>;
-    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZero<i16>;
-    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZero<i32>;
-    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZero<i64>;
-    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZero<i128>;
-    #[stable(feature = "signed_nonzero", since = "1.34.0")] NonZero<isize>;
-}
-
-#[stable(feature = "nonnull", since = "1.25.0")]
-impl<T> SpecOptionPartialEq for crate::ptr::NonNull<T> {
+// Manually implementing here somewhat improves codegen for
+// https://github.com/rust-lang/rust/issues/49892, although still
+// not optimal.
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T: PartialOrd> PartialOrd for Option<T> {
     #[inline]
-    fn eq(l: &Option<Self>, r: &Option<Self>) -> bool {
-        l.map(Self::as_ptr).unwrap_or_else(|| crate::ptr::null_mut())
-            == r.map(Self::as_ptr).unwrap_or_else(|| crate::ptr::null_mut())
+    fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
+        match (self, other) {
+            (Some(l), Some(r)) => l.partial_cmp(r),
+            (Some(_), None) => Some(cmp::Ordering::Greater),
+            (None, Some(_)) => Some(cmp::Ordering::Less),
+            (None, None) => Some(cmp::Ordering::Equal),
+        }
     }
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
-impl SpecOptionPartialEq for cmp::Ordering {
+impl<T: Ord> Ord for Option<T> {
     #[inline]
-    fn eq(l: &Option<Self>, r: &Option<Self>) -> bool {
-        l.map_or(2, |x| x as i8) == r.map_or(2, |x| x as i8)
+    fn cmp(&self, other: &Self) -> cmp::Ordering {
+        match (self, other) {
+            (Some(l), Some(r)) => l.cmp(r),
+            (Some(_), None) => cmp::Ordering::Greater,
+            (None, Some(_)) => cmp::Ordering::Less,
+            (None, None) => cmp::Ordering::Equal,
+        }
     }
 }
 
diff --git a/library/core/src/prelude/v1.rs b/library/core/src/prelude/v1.rs
index 10525a16f3a..29f73bb4942 100644
--- a/library/core/src/prelude/v1.rs
+++ b/library/core/src/prelude/v1.rs
@@ -103,3 +103,11 @@ pub use crate::macros::builtin::cfg_eval;
     reason = "placeholder syntax for type ascription"
 )]
 pub use crate::macros::builtin::type_ascribe;
+
+#[cfg(not(bootstrap))]
+#[unstable(
+    feature = "deref_patterns",
+    issue = "87121",
+    reason = "placeholder syntax for deref patterns"
+)]
+pub use crate::macros::builtin::deref;
diff --git a/library/panic_unwind/src/emcc.rs b/library/panic_unwind/src/emcc.rs
index af18e19337c..fed4c52e83c 100644
--- a/library/panic_unwind/src/emcc.rs
+++ b/library/panic_unwind/src/emcc.rs
@@ -84,7 +84,7 @@ pub unsafe fn cleanup(ptr: *mut u8) -> Box<dyn Any + Send> {
         super::__rust_foreign_exception();
     }
 
-    let was_caught = (*adjusted_ptr).caught.swap(true, Ordering::SeqCst);
+    let was_caught = (*adjusted_ptr).caught.swap(true, Ordering::Relaxed);
     if was_caught {
         // Since cleanup() isn't allowed to panic, we just abort instead.
         intrinsics::abort();
diff --git a/library/proc_macro/src/bridge/handle.rs b/library/proc_macro/src/bridge/handle.rs
index 894acae217e..8c53bb609f6 100644
--- a/library/proc_macro/src/bridge/handle.rs
+++ b/library/proc_macro/src/bridge/handle.rs
@@ -21,7 +21,7 @@ impl<T> OwnedStore<T> {
     pub(super) fn new(counter: &'static AtomicU32) -> Self {
         // Ensure the handle counter isn't 0, which would panic later,
         // when `NonZero::new` (aka `Handle::new`) is called in `alloc`.
-        assert_ne!(counter.load(Ordering::SeqCst), 0);
+        assert_ne!(counter.load(Ordering::Relaxed), 0);
 
         OwnedStore { counter, data: BTreeMap::new() }
     }
@@ -29,7 +29,7 @@ impl<T> OwnedStore<T> {
 
 impl<T> OwnedStore<T> {
     pub(super) fn alloc(&mut self, x: T) -> Handle {
-        let counter = self.counter.fetch_add(1, Ordering::SeqCst);
+        let counter = self.counter.fetch_add(1, Ordering::Relaxed);
         let handle = Handle::new(counter).expect("`proc_macro` handle counter overflowed");
         assert!(self.data.insert(handle, x).is_none());
         handle
diff --git a/library/std/src/alloc.rs b/library/std/src/alloc.rs
index a834b36697c..dc0e302a810 100644
--- a/library/std/src/alloc.rs
+++ b/library/std/src/alloc.rs
@@ -329,7 +329,7 @@ static HOOK: AtomicPtr<()> = AtomicPtr::new(ptr::null_mut());
 /// ```
 #[unstable(feature = "alloc_error_hook", issue = "51245")]
 pub fn set_alloc_error_hook(hook: fn(Layout)) {
-    HOOK.store(hook as *mut (), Ordering::SeqCst);
+    HOOK.store(hook as *mut (), Ordering::Release);
 }
 
 /// Unregisters the current allocation error hook, returning it.
@@ -339,7 +339,7 @@ pub fn set_alloc_error_hook(hook: fn(Layout)) {
 /// If no custom hook is registered, the default hook will be returned.
 #[unstable(feature = "alloc_error_hook", issue = "51245")]
 pub fn take_alloc_error_hook() -> fn(Layout) {
-    let hook = HOOK.swap(ptr::null_mut(), Ordering::SeqCst);
+    let hook = HOOK.swap(ptr::null_mut(), Ordering::Acquire);
     if hook.is_null() { default_alloc_error_hook } else { unsafe { mem::transmute(hook) } }
 }
 
@@ -362,7 +362,7 @@ fn default_alloc_error_hook(layout: Layout) {
 #[alloc_error_handler]
 #[unstable(feature = "alloc_internals", issue = "none")]
 pub fn rust_oom(layout: Layout) -> ! {
-    let hook = HOOK.load(Ordering::SeqCst);
+    let hook = HOOK.load(Ordering::Acquire);
     let hook: fn(Layout) =
         if hook.is_null() { default_alloc_error_hook } else { unsafe { mem::transmute(hook) } };
     hook(layout);
diff --git a/library/std/src/net/test.rs b/library/std/src/net/test.rs
index 37937b5ea95..d318d457f35 100644
--- a/library/std/src/net/test.rs
+++ b/library/std/src/net/test.rs
@@ -7,12 +7,12 @@ use crate::sync::atomic::{AtomicUsize, Ordering};
 static PORT: AtomicUsize = AtomicUsize::new(0);
 
 pub fn next_test_ip4() -> SocketAddr {
-    let port = PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port();
+    let port = PORT.fetch_add(1, Ordering::Relaxed) as u16 + base_port();
     SocketAddr::V4(SocketAddrV4::new(Ipv4Addr::new(127, 0, 0, 1), port))
 }
 
 pub fn next_test_ip6() -> SocketAddr {
-    let port = PORT.fetch_add(1, Ordering::SeqCst) as u16 + base_port();
+    let port = PORT.fetch_add(1, Ordering::Relaxed) as u16 + base_port();
     SocketAddr::V6(SocketAddrV6::new(Ipv6Addr::new(0, 0, 0, 0, 0, 0, 0, 1), port, 0, 0))
 }
 
diff --git a/library/std/src/os/freebsd/net.rs b/library/std/src/os/freebsd/net.rs
index 33990d54caa..b7e0fdc0a9a 100644
--- a/library/std/src/os/freebsd/net.rs
+++ b/library/std/src/os/freebsd/net.rs
@@ -2,6 +2,7 @@
 
 #![unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
 
+use crate::ffi::CStr;
 use crate::io;
 use crate::os::unix::net;
 use crate::sealed::Sealed;
@@ -40,6 +41,15 @@ pub trait UnixSocketExt: Sealed {
     /// ```
     #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
     fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()>;
+
+    /// Get a filter name if one had been set previously on the socket.
+    #[unstable(feature = "acceptfilter", issue = "121891")]
+    fn acceptfilter(&self) -> io::Result<&CStr>;
+
+    /// Set or disable a filter on the socket to filter incoming connections
+    /// to defer it before accept(2)
+    #[unstable(feature = "acceptfilter", issue = "121891")]
+    fn set_acceptfilter(&self, name: &CStr) -> io::Result<()>;
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -51,6 +61,14 @@ impl UnixSocketExt for net::UnixDatagram {
     fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()> {
         self.as_inner().set_local_creds_persistent(local_creds_persistent)
     }
+
+    fn acceptfilter(&self) -> io::Result<&CStr> {
+        self.as_inner().acceptfilter()
+    }
+
+    fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+        self.as_inner().set_acceptfilter(name)
+    }
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -62,4 +80,12 @@ impl UnixSocketExt for net::UnixStream {
     fn set_local_creds_persistent(&self, local_creds_persistent: bool) -> io::Result<()> {
         self.as_inner().set_local_creds_persistent(local_creds_persistent)
     }
+
+    fn acceptfilter(&self) -> io::Result<&CStr> {
+        self.as_inner().acceptfilter()
+    }
+
+    fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+        self.as_inner().set_acceptfilter(name)
+    }
 }
diff --git a/library/std/src/os/netbsd/net.rs b/library/std/src/os/netbsd/net.rs
index 5c82f43077d..b9679c7b3af 100644
--- a/library/std/src/os/netbsd/net.rs
+++ b/library/std/src/os/netbsd/net.rs
@@ -2,6 +2,7 @@
 
 #![unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
 
+use crate::ffi::CStr;
 use crate::io;
 use crate::os::unix::net;
 use crate::sealed::Sealed;
@@ -40,6 +41,15 @@ pub trait UnixSocketExt: Sealed {
     /// ```
     #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
     fn set_local_creds(&self, local_creds: bool) -> io::Result<()>;
+
+    /// Get a filter name if one had been set previously on the socket.
+    #[unstable(feature = "acceptfilter", issue = "121891")]
+    fn acceptfilter(&self) -> io::Result<&CStr>;
+
+    /// Set or disable a filter on the socket to filter incoming connections
+    /// to defer it before accept(2)
+    #[unstable(feature = "acceptfilter", issue = "121891")]
+    fn set_acceptfilter(&self, name: &CStr) -> io::Result<()>;
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -51,6 +61,14 @@ impl UnixSocketExt for net::UnixDatagram {
     fn set_local_creds(&self, local_creds: bool) -> io::Result<()> {
         self.as_inner().set_local_creds(local_creds)
     }
+
+    fn acceptfilter(&self) -> io::Result<&CStr> {
+        self.as_inner().acceptfilter()
+    }
+
+    fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+        self.as_inner().set_acceptfilter(name)
+    }
 }
 
 #[unstable(feature = "unix_socket_ancillary_data", issue = "76915")]
@@ -62,4 +80,12 @@ impl UnixSocketExt for net::UnixStream {
     fn set_local_creds(&self, local_creds: bool) -> io::Result<()> {
         self.as_inner().set_local_creds(local_creds)
     }
+
+    fn acceptfilter(&self) -> io::Result<&CStr> {
+        self.as_inner().acceptfilter()
+    }
+
+    fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+        self.as_inner().set_acceptfilter(name)
+    }
 }
diff --git a/library/std/src/panicking.rs b/library/std/src/panicking.rs
index 464a46264cb..b0bcab7994c 100644
--- a/library/std/src/panicking.rs
+++ b/library/std/src/panicking.rs
@@ -272,7 +272,7 @@ fn default_hook(info: &PanicInfo<'_>) {
                 drop(backtrace::print(err, crate::backtrace_rs::PrintFmt::Full))
             }
             Some(BacktraceStyle::Off) => {
-                if FIRST_PANIC.swap(false, Ordering::SeqCst) {
+                if FIRST_PANIC.swap(false, Ordering::Relaxed) {
                     let _ = writeln!(
                         err,
                         "note: run with `RUST_BACKTRACE=1` environment variable to display a \
diff --git a/library/std/src/prelude/v1.rs b/library/std/src/prelude/v1.rs
index 7a7a7737635..36fa4e88b5b 100644
--- a/library/std/src/prelude/v1.rs
+++ b/library/std/src/prelude/v1.rs
@@ -91,6 +91,15 @@ pub use core::prelude::v1::cfg_eval;
 )]
 pub use core::prelude::v1::type_ascribe;
 
+#[cfg(not(bootstrap))]
+// Do not `doc(no_inline)` either.
+#[unstable(
+    feature = "deref_patterns",
+    issue = "87121",
+    reason = "placeholder syntax for deref patterns"
+)]
+pub use core::prelude::v1::deref;
+
 // The file so far is equivalent to core/src/prelude/v1.rs. It is duplicated
 // rather than glob imported because we want docs to show these re-exports as
 // pointing to within `std`.
diff --git a/library/std/src/sync/condvar/tests.rs b/library/std/src/sync/condvar/tests.rs
index 24f467f0b03..12d13a6b20b 100644
--- a/library/std/src/sync/condvar/tests.rs
+++ b/library/std/src/sync/condvar/tests.rs
@@ -170,14 +170,14 @@ fn wait_timeout_wake() {
         let t = thread::spawn(move || {
             let _g = m2.lock().unwrap();
             thread::sleep(Duration::from_millis(1));
-            notified_copy.store(true, Ordering::SeqCst);
+            notified_copy.store(true, Ordering::Relaxed);
             c2.notify_one();
         });
         let (g, timeout_res) = c.wait_timeout(g, Duration::from_millis(u64::MAX)).unwrap();
         assert!(!timeout_res.timed_out());
         // spurious wakeups mean this isn't necessarily true
         // so execute test again, if not notified
-        if !notified.load(Ordering::SeqCst) {
+        if !notified.load(Ordering::Relaxed) {
             t.join().unwrap();
             continue;
         }
diff --git a/library/std/src/sys/pal/unix/net.rs b/library/std/src/sys/pal/unix/net.rs
index 09750b6ffc8..1f140f7844f 100644
--- a/library/std/src/sys/pal/unix/net.rs
+++ b/library/std/src/sys/pal/unix/net.rs
@@ -453,6 +453,37 @@ impl Socket {
         Ok(raw as u32)
     }
 
+    #[cfg(any(target_os = "freebsd", target_os = "netbsd"))]
+    pub fn set_acceptfilter(&self, name: &CStr) -> io::Result<()> {
+        if !name.to_bytes().is_empty() {
+            const AF_NAME_MAX: usize = 16;
+            let mut buf = [0; AF_NAME_MAX];
+            for (src, dst) in name.to_bytes().iter().zip(&mut buf[..AF_NAME_MAX - 1]) {
+                *dst = *src as i8;
+            }
+            let mut arg: libc::accept_filter_arg = unsafe { mem::zeroed() };
+            arg.af_name = buf;
+            setsockopt(self, libc::SOL_SOCKET, libc::SO_ACCEPTFILTER, &mut arg)
+        } else {
+            setsockopt(
+                self,
+                libc::SOL_SOCKET,
+                libc::SO_ACCEPTFILTER,
+                core::ptr::null_mut() as *mut c_void,
+            )
+        }
+    }
+
+    #[cfg(any(target_os = "freebsd", target_os = "netbsd"))]
+    pub fn acceptfilter(&self) -> io::Result<&CStr> {
+        let arg: libc::accept_filter_arg =
+            getsockopt(self, libc::SOL_SOCKET, libc::SO_ACCEPTFILTER)?;
+        let s: &[u8] =
+            unsafe { core::slice::from_raw_parts(arg.af_name.as_ptr() as *const u8, 16) };
+        let name = CStr::from_bytes_with_nul(s).unwrap();
+        Ok(name)
+    }
+
     #[cfg(any(target_os = "android", target_os = "linux",))]
     pub fn set_passcred(&self, passcred: bool) -> io::Result<()> {
         setsockopt(self, libc::SOL_SOCKET, libc::SO_PASSCRED, passcred as libc::c_int)
diff --git a/library/std/src/sys/pal/unix/thread_parking/pthread.rs b/library/std/src/sys/pal/unix/thread_parking/pthread.rs
index ae805d84399..bb79cf9548e 100644
--- a/library/std/src/sys/pal/unix/thread_parking/pthread.rs
+++ b/library/std/src/sys/pal/unix/thread_parking/pthread.rs
@@ -5,7 +5,7 @@ use crate::marker::PhantomPinned;
 use crate::pin::Pin;
 use crate::ptr::addr_of_mut;
 use crate::sync::atomic::AtomicUsize;
-use crate::sync::atomic::Ordering::SeqCst;
+use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};
 #[cfg(not(target_os = "nto"))]
 use crate::sys::time::TIMESPEC_MAX;
 #[cfg(target_os = "nto")]
@@ -150,16 +150,18 @@ impl Parker {
 
     // This implementation doesn't require `unsafe`, but other implementations
     // may assume this is only called by the thread that owns the Parker.
+    //
+    // For memory ordering, see std/src/sys_common/thread_parking/futex.rs
     pub unsafe fn park(self: Pin<&Self>) {
         // If we were previously notified then we consume this notification and
         // return quickly.
-        if self.state.compare_exchange(NOTIFIED, EMPTY, SeqCst, SeqCst).is_ok() {
+        if self.state.compare_exchange(NOTIFIED, EMPTY, Acquire, Relaxed).is_ok() {
             return;
         }
 
         // Otherwise we need to coordinate going to sleep
         lock(self.lock.get());
-        match self.state.compare_exchange(EMPTY, PARKED, SeqCst, SeqCst) {
+        match self.state.compare_exchange(EMPTY, PARKED, Relaxed, Relaxed) {
             Ok(_) => {}
             Err(NOTIFIED) => {
                 // We must read here, even though we know it will be `NOTIFIED`.
@@ -168,7 +170,7 @@ impl Parker {
                 // acquire operation that synchronizes with that `unpark` to observe
                 // any writes it made before the call to unpark. To do that we must
                 // read from the write it made to `state`.
-                let old = self.state.swap(EMPTY, SeqCst);
+                let old = self.state.swap(EMPTY, Acquire);
 
                 unlock(self.lock.get());
 
@@ -185,7 +187,7 @@ impl Parker {
         loop {
             wait(self.cvar.get(), self.lock.get());
 
-            match self.state.compare_exchange(NOTIFIED, EMPTY, SeqCst, SeqCst) {
+            match self.state.compare_exchange(NOTIFIED, EMPTY, Acquire, Relaxed) {
                 Ok(_) => break, // got a notification
                 Err(_) => {}    // spurious wakeup, go back to sleep
             }
@@ -201,16 +203,16 @@ impl Parker {
         // Like `park` above we have a fast path for an already-notified thread, and
         // afterwards we start coordinating for a sleep.
         // return quickly.
-        if self.state.compare_exchange(NOTIFIED, EMPTY, SeqCst, SeqCst).is_ok() {
+        if self.state.compare_exchange(NOTIFIED, EMPTY, Acquire, Relaxed).is_ok() {
             return;
         }
 
         lock(self.lock.get());
-        match self.state.compare_exchange(EMPTY, PARKED, SeqCst, SeqCst) {
+        match self.state.compare_exchange(EMPTY, PARKED, Relaxed, Relaxed) {
             Ok(_) => {}
             Err(NOTIFIED) => {
                 // We must read again here, see `park`.
-                let old = self.state.swap(EMPTY, SeqCst);
+                let old = self.state.swap(EMPTY, Acquire);
                 unlock(self.lock.get());
 
                 assert_eq!(old, NOTIFIED, "park state changed unexpectedly");
@@ -228,7 +230,7 @@ impl Parker {
         // parked.
         wait_timeout(self.cvar.get(), self.lock.get(), dur);
 
-        match self.state.swap(EMPTY, SeqCst) {
+        match self.state.swap(EMPTY, Acquire) {
             NOTIFIED => unlock(self.lock.get()), // got a notification, hurray!
             PARKED => unlock(self.lock.get()),   // no notification, alas
             n => {
@@ -245,7 +247,7 @@ impl Parker {
         // `state` is already `NOTIFIED`. That is why this must be a swap
         // rather than a compare-and-swap that returns if it reads `NOTIFIED`
         // on failure.
-        match self.state.swap(NOTIFIED, SeqCst) {
+        match self.state.swap(NOTIFIED, Release) {
             EMPTY => return,    // no one was waiting
             NOTIFIED => return, // already unparked
             PARKED => {}        // gotta go wake someone up
diff --git a/library/std/src/sys/pal/wasm/alloc.rs b/library/std/src/sys/pal/wasm/alloc.rs
index 6dceb1689a8..b74ce0d4742 100644
--- a/library/std/src/sys/pal/wasm/alloc.rs
+++ b/library/std/src/sys/pal/wasm/alloc.rs
@@ -57,7 +57,10 @@ unsafe impl GlobalAlloc for System {
 
 #[cfg(target_feature = "atomics")]
 mod lock {
-    use crate::sync::atomic::{AtomicI32, Ordering::SeqCst};
+    use crate::sync::atomic::{
+        AtomicI32,
+        Ordering::{Acquire, Release},
+    };
 
     static LOCKED: AtomicI32 = AtomicI32::new(0);
 
@@ -65,7 +68,7 @@ mod lock {
 
     pub fn lock() -> DropLock {
         loop {
-            if LOCKED.swap(1, SeqCst) == 0 {
+            if LOCKED.swap(1, Acquire) == 0 {
                 return DropLock;
             }
             // Ok so here's where things get a little depressing. At this point
@@ -143,7 +146,7 @@ mod lock {
 
     impl Drop for DropLock {
         fn drop(&mut self) {
-            let r = LOCKED.swap(0, SeqCst);
+            let r = LOCKED.swap(0, Release);
             debug_assert_eq!(r, 1);
 
             // Note that due to the above logic we don't actually need to wake
diff --git a/library/std/src/sys/pal/windows/pipe.rs b/library/std/src/sys/pal/windows/pipe.rs
index 013f588676a..dfa938d4d57 100644
--- a/library/std/src/sys/pal/windows/pipe.rs
+++ b/library/std/src/sys/pal/windows/pipe.rs
@@ -7,7 +7,7 @@ use crate::path::Path;
 use crate::ptr;
 use crate::slice;
 use crate::sync::atomic::AtomicUsize;
-use crate::sync::atomic::Ordering::SeqCst;
+use crate::sync::atomic::Ordering::Relaxed;
 use crate::sys::c;
 use crate::sys::fs::{File, OpenOptions};
 use crate::sys::handle::Handle;
@@ -214,11 +214,11 @@ pub fn spawn_pipe_relay(
 fn random_number() -> usize {
     static N: AtomicUsize = AtomicUsize::new(0);
     loop {
-        if N.load(SeqCst) != 0 {
-            return N.fetch_add(1, SeqCst);
+        if N.load(Relaxed) != 0 {
+            return N.fetch_add(1, Relaxed);
         }
 
-        N.store(hashmap_random_keys().0 as usize, SeqCst);
+        N.store(hashmap_random_keys().0 as usize, Relaxed);
     }
 }
 
diff --git a/library/std/src/sys/pal/xous/alloc.rs b/library/std/src/sys/pal/xous/alloc.rs
index 0d540e95520..601411173aa 100644
--- a/library/std/src/sys/pal/xous/alloc.rs
+++ b/library/std/src/sys/pal/xous/alloc.rs
@@ -46,7 +46,10 @@ unsafe impl GlobalAlloc for System {
 }
 
 mod lock {
-    use crate::sync::atomic::{AtomicI32, Ordering::SeqCst};
+    use crate::sync::atomic::{
+        AtomicI32,
+        Ordering::{Acquire, Release},
+    };
 
     static LOCKED: AtomicI32 = AtomicI32::new(0);
 
@@ -54,7 +57,7 @@ mod lock {
 
     pub fn lock() -> DropLock {
         loop {
-            if LOCKED.swap(1, SeqCst) == 0 {
+            if LOCKED.swap(1, Acquire) == 0 {
                 return DropLock;
             }
             crate::os::xous::ffi::do_yield();
@@ -63,7 +66,7 @@ mod lock {
 
     impl Drop for DropLock {
         fn drop(&mut self) {
-            let r = LOCKED.swap(0, SeqCst);
+            let r = LOCKED.swap(0, Release);
             debug_assert_eq!(r, 1);
         }
     }
diff --git a/library/std/src/sys/pal/xous/net/tcpstream.rs b/library/std/src/sys/pal/xous/net/tcpstream.rs
index 7149678118a..aebef02acda 100644
--- a/library/std/src/sys/pal/xous/net/tcpstream.rs
+++ b/library/std/src/sys/pal/xous/net/tcpstream.rs
@@ -406,7 +406,7 @@ impl TcpStream {
     }
 
     pub fn set_nonblocking(&self, nonblocking: bool) -> io::Result<()> {
-        self.nonblocking.store(nonblocking, Ordering::SeqCst);
+        self.nonblocking.store(nonblocking, Ordering::Relaxed);
         Ok(())
     }
 }
diff --git a/library/std/src/sys/pal/xous/thread_local_key.rs b/library/std/src/sys/pal/xous/thread_local_key.rs
index 59a668c3df6..2aaf46d0244 100644
--- a/library/std/src/sys/pal/xous/thread_local_key.rs
+++ b/library/std/src/sys/pal/xous/thread_local_key.rs
@@ -2,7 +2,7 @@ use crate::mem::ManuallyDrop;
 use crate::ptr;
 use crate::sync::atomic::AtomicPtr;
 use crate::sync::atomic::AtomicUsize;
-use crate::sync::atomic::Ordering::SeqCst;
+use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};
 use core::arch::asm;
 
 use crate::os::xous::ffi::{map_memory, unmap_memory, MemoryFlags};
@@ -92,7 +92,7 @@ fn tls_table() -> &'static mut [*mut u8] {
 pub unsafe fn create(dtor: Option<Dtor>) -> Key {
     // Allocate a new TLS key. These keys are shared among all threads.
     #[allow(unused_unsafe)]
-    let key = unsafe { TLS_KEY_INDEX.fetch_add(1, SeqCst) };
+    let key = unsafe { TLS_KEY_INDEX.fetch_add(1, Relaxed) };
     if let Some(f) = dtor {
         unsafe { register_dtor(key, f) };
     }
@@ -154,11 +154,11 @@ unsafe fn register_dtor(key: Key, dtor: Dtor) {
     let mut node = ManuallyDrop::new(Box::new(Node { key, dtor, next: ptr::null_mut() }));
 
     #[allow(unused_unsafe)]
-    let mut head = unsafe { DTORS.load(SeqCst) };
+    let mut head = unsafe { DTORS.load(Acquire) };
     loop {
         node.next = head;
         #[allow(unused_unsafe)]
-        match unsafe { DTORS.compare_exchange(head, &mut **node, SeqCst, SeqCst) } {
+        match unsafe { DTORS.compare_exchange(head, &mut **node, Release, Acquire) } {
             Ok(_) => return, // nothing to drop, we successfully added the node to the list
             Err(cur) => head = cur,
         }
@@ -199,7 +199,7 @@ unsafe fn run_dtors() {
         }
         any_run = false;
         #[allow(unused_unsafe)]
-        let mut cur = unsafe { DTORS.load(SeqCst) };
+        let mut cur = unsafe { DTORS.load(Acquire) };
         while !cur.is_null() {
             let ptr = unsafe { get((*cur).key) };
 
diff --git a/library/std/src/sys/sync/mutex/xous.rs b/library/std/src/sys/sync/mutex/xous.rs
index a8c9518ff0b..1426e48f8b7 100644
--- a/library/std/src/sys/sync/mutex/xous.rs
+++ b/library/std/src/sys/sync/mutex/xous.rs
@@ -1,6 +1,9 @@
 use crate::os::xous::ffi::{blocking_scalar, do_yield};
 use crate::os::xous::services::{ticktimer_server, TicktimerScalar};
-use crate::sync::atomic::{AtomicBool, AtomicUsize, Ordering::Relaxed, Ordering::SeqCst};
+use crate::sync::atomic::{
+    AtomicBool, AtomicUsize,
+    Ordering::{Acquire, Relaxed, Release},
+};
 
 pub struct Mutex {
     /// The "locked" value indicates how many threads are waiting on this
@@ -68,7 +71,7 @@ impl Mutex {
 
     #[inline]
     pub unsafe fn unlock(&self) {
-        let prev = self.locked.fetch_sub(1, SeqCst);
+        let prev = self.locked.fetch_sub(1, Release);
 
         // If the previous value was 1, then this was a "fast path" unlock, so no
         // need to involve the Ticktimer server
@@ -89,12 +92,12 @@ impl Mutex {
 
     #[inline]
     pub unsafe fn try_lock(&self) -> bool {
-        self.locked.compare_exchange(0, 1, SeqCst, SeqCst).is_ok()
+        self.locked.compare_exchange(0, 1, Acquire, Relaxed).is_ok()
     }
 
     #[inline]
     pub unsafe fn try_lock_or_poison(&self) -> bool {
-        self.locked.fetch_add(1, SeqCst) == 0
+        self.locked.fetch_add(1, Acquire) == 0
     }
 }
 
diff --git a/library/std/src/sys_common/thread_local_key.rs b/library/std/src/sys_common/thread_local_key.rs
index 204834984a2..7dcc1141099 100644
--- a/library/std/src/sys_common/thread_local_key.rs
+++ b/library/std/src/sys_common/thread_local_key.rs
@@ -128,7 +128,7 @@ impl StaticKey {
 
     #[inline]
     unsafe fn key(&self) -> imp::Key {
-        match self.key.load(Ordering::Relaxed) {
+        match self.key.load(Ordering::Acquire) {
             KEY_SENTVAL => self.lazy_init() as imp::Key,
             n => n as imp::Key,
         }
@@ -156,8 +156,8 @@ impl StaticKey {
         match self.key.compare_exchange(
             KEY_SENTVAL,
             key as usize,
-            Ordering::SeqCst,
-            Ordering::SeqCst,
+            Ordering::Release,
+            Ordering::Acquire,
         ) {
             // The CAS succeeded, so we've created the actual key
             Ok(_) => key as usize,
diff --git a/library/std/src/thread/local/tests.rs b/library/std/src/thread/local/tests.rs
index 964c7fc5b0c..25019b554bb 100644
--- a/library/std/src/thread/local/tests.rs
+++ b/library/std/src/thread/local/tests.rs
@@ -255,6 +255,9 @@ fn join_orders_after_tls_destructors() {
     // observe the channel in the `THREAD1_WAITING` state. If this does occur,
     // we switch to the “poison” state `THREAD2_JOINED` and panic all around.
     // (This is equivalent to “sending” from an alternate producer thread.)
+    //
+    // Relaxed memory ordering is fine because and spawn()/join() already provide all the
+    // synchronization we need here.
     const FRESH: u8 = 0;
     const THREAD2_LAUNCHED: u8 = 1;
     const THREAD1_WAITING: u8 = 2;
@@ -263,7 +266,7 @@ fn join_orders_after_tls_destructors() {
     static SYNC_STATE: AtomicU8 = AtomicU8::new(FRESH);
 
     for _ in 0..10 {
-        SYNC_STATE.store(FRESH, Ordering::SeqCst);
+        SYNC_STATE.store(FRESH, Ordering::Relaxed);
 
         let jh = thread::Builder::new()
             .name("thread1".into())
@@ -272,7 +275,7 @@ fn join_orders_after_tls_destructors() {
 
                 impl Drop for TlDrop {
                     fn drop(&mut self) {
-                        let mut sync_state = SYNC_STATE.swap(THREAD1_WAITING, Ordering::SeqCst);
+                        let mut sync_state = SYNC_STATE.swap(THREAD1_WAITING, Ordering::Relaxed);
                         loop {
                             match sync_state {
                                 THREAD2_LAUNCHED | THREAD1_WAITING => thread::yield_now(),
@@ -282,7 +285,7 @@ fn join_orders_after_tls_destructors() {
                                 ),
                                 v => unreachable!("sync state: {}", v),
                             }
-                            sync_state = SYNC_STATE.load(Ordering::SeqCst);
+                            sync_state = SYNC_STATE.load(Ordering::Relaxed);
                         }
                     }
                 }
@@ -294,7 +297,7 @@ fn join_orders_after_tls_destructors() {
                 TL_DROP.with(|_| {});
 
                 loop {
-                    match SYNC_STATE.load(Ordering::SeqCst) {
+                    match SYNC_STATE.load(Ordering::Relaxed) {
                         FRESH => thread::yield_now(),
                         THREAD2_LAUNCHED => break,
                         v => unreachable!("sync state: {}", v),
@@ -306,9 +309,9 @@ fn join_orders_after_tls_destructors() {
         let jh2 = thread::Builder::new()
             .name("thread2".into())
             .spawn(move || {
-                assert_eq!(SYNC_STATE.swap(THREAD2_LAUNCHED, Ordering::SeqCst), FRESH);
+                assert_eq!(SYNC_STATE.swap(THREAD2_LAUNCHED, Ordering::Relaxed), FRESH);
                 jh.join().unwrap();
-                match SYNC_STATE.swap(THREAD2_JOINED, Ordering::SeqCst) {
+                match SYNC_STATE.swap(THREAD2_JOINED, Ordering::Relaxed) {
                     MAIN_THREAD_RENDEZVOUS => return,
                     THREAD2_LAUNCHED | THREAD1_WAITING => {
                         panic!("Thread 2 running after thread 1 join before main thread rendezvous")
@@ -322,8 +325,8 @@ fn join_orders_after_tls_destructors() {
             match SYNC_STATE.compare_exchange(
                 THREAD1_WAITING,
                 MAIN_THREAD_RENDEZVOUS,
-                Ordering::SeqCst,
-                Ordering::SeqCst,
+                Ordering::Relaxed,
+                Ordering::Relaxed,
             ) {
                 Ok(_) => break,
                 Err(FRESH) => thread::yield_now(),
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 64bb7bf01f7..d8397ab51de 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -1009,15 +1009,23 @@ impl Build {
         let result = if !output.status.success() {
             if print_error {
                 println!(
-                    "\n\ncommand did not execute successfully: {:?}\n\
-                    expected success, got: {}\n\n\
-                    stdout ----\n{}\n\
-                    stderr ----\n{}\n\n",
-                    command.command,
+                    "\n\nCommand did not execute successfully.\
+                    \nExpected success, got: {}",
                     output.status,
-                    String::from_utf8_lossy(&output.stdout),
-                    String::from_utf8_lossy(&output.stderr)
                 );
+
+                if !self.is_verbose() {
+                    println!("Add `-v` to see more details.\n");
+                }
+
+                self.verbose(|| {
+                    println!(
+                        "\nSTDOUT ----\n{}\n\
+                        STDERR ----\n{}\n",
+                        String::from_utf8_lossy(&output.stdout),
+                        String::from_utf8_lossy(&output.stderr)
+                    )
+                });
             }
             Err(())
         } else {
@@ -1389,6 +1397,13 @@ impl Build {
         if let Some(path) = finder.maybe_have("wasmtime") {
             if let Ok(mut path) = path.into_os_string().into_string() {
                 path.push_str(" run -C cache=n --dir .");
+                // Make sure that tests have access to RUSTC_BOOTSTRAP. This (for example) is
+                // required for libtest to work on beta/stable channels.
+                //
+                // NB: with Wasmtime 20 this can change to `-S inherit-env` to
+                // inherit the entire environment rather than just this single
+                // environment variable.
+                path.push_str(" --env RUSTC_BOOTSTRAP");
                 return Some(path);
             }
         }
diff --git a/src/ci/docker/host-x86_64/test-various/Dockerfile b/src/ci/docker/host-x86_64/test-various/Dockerfile
index 944d9aed319..4de9afdb171 100644
--- a/src/ci/docker/host-x86_64/test-various/Dockerfile
+++ b/src/ci/docker/host-x86_64/test-various/Dockerfile
@@ -55,9 +55,9 @@ ENV RUST_CONFIGURE_ARGS \
 ENV NO_DEBUG_ASSERTIONS=1
 ENV NO_OVERFLOW_CHECKS=1
 
-RUN curl -L https://github.com/bytecodealliance/wasmtime/releases/download/v18.0.2/wasmtime-v18.0.2-x86_64-linux.tar.xz | \
+RUN curl -L https://github.com/bytecodealliance/wasmtime/releases/download/v19.0.0/wasmtime-v19.0.0-x86_64-linux.tar.xz | \
   tar -xJ
-ENV PATH "$PATH:/wasmtime-v18.0.2-x86_64-linux"
+ENV PATH "$PATH:/wasmtime-v19.0.0-x86_64-linux"
 
 ENV WASM_TARGETS=wasm32-wasip1
 ENV WASM_SCRIPT python3 /checkout/x.py --stage 2 test --host='' --target $WASM_TARGETS \
diff --git a/src/doc/rustc/src/platform-support.md b/src/doc/rustc/src/platform-support.md
index 274745b9082..75d38dd20bd 100644
--- a/src/doc/rustc/src/platform-support.md
+++ b/src/doc/rustc/src/platform-support.md
@@ -339,6 +339,7 @@ target | std | host | notes
 `riscv32gc-unknown-linux-gnu` |   |   | RISC-V Linux (kernel 5.4, glibc 2.33)
 `riscv32gc-unknown-linux-musl` |   |   | RISC-V Linux (kernel 5.4, musl 1.2.3 + RISCV32 support patches)
 [`riscv32im-risc0-zkvm-elf`](platform-support/riscv32im-risc0-zkvm-elf.md) | ? |  | RISC Zero's zero-knowledge Virtual Machine (RV32IM ISA)
+[`riscv32ima-unknown-none-elf`](platform-support/riscv32-unknown-none-elf.md) | * |  | Bare RISC-V (RV32IMA ISA)
 [`riscv32imac-unknown-xous-elf`](platform-support/riscv32imac-unknown-xous-elf.md) | ? |  | RISC-V Xous (RV32IMAC ISA)
 [`riscv32imc-esp-espidf`](platform-support/esp-idf.md) | ✓ |  | RISC-V ESP-IDF
 [`riscv32imac-esp-espidf`](platform-support/esp-idf.md) | ✓ |  | RISC-V ESP-IDF
diff --git a/src/doc/rustc/src/platform-support/riscv32-unknown-none-elf.md b/src/doc/rustc/src/platform-support/riscv32-unknown-none-elf.md
index 739b12bad8b..9a27a568b57 100644
--- a/src/doc/rustc/src/platform-support/riscv32-unknown-none-elf.md
+++ b/src/doc/rustc/src/platform-support/riscv32-unknown-none-elf.md
@@ -1,9 +1,13 @@
-# `riscv32{i,im,imc,imac,imafc}-unknown-none-elf`
+# `riscv32{i,im,ima,imc,imac,imafc}-unknown-none-elf`
 
 **Tier: 2**
 
 Bare-metal target for RISC-V CPUs with the RV32I, RV32IM, RV32IMC, RV32IMAFC and RV32IMAC ISAs.
 
+**Tier: 3**
+
+Bare-metal target for RISC-V CPUs with the RV32IMA ISA.
+
 ## Target maintainers
 
 * Rust Embedded Working Group, [RISC-V team](https://github.com/rust-embedded/wg#the-risc-v-team)
diff --git a/src/doc/unstable-book/src/language-features/postfix-match.md b/src/doc/unstable-book/src/language-features/postfix-match.md
new file mode 100644
index 00000000000..cd6b6a7442c
--- /dev/null
+++ b/src/doc/unstable-book/src/language-features/postfix-match.md
@@ -0,0 +1,22 @@
+# `postfix-match`
+
+`postfix-match` adds the feature for matching upon values postfix
+the expressions that generate the values.
+
+```rust,edition2021
+#![feature(postfix_match)]
+
+enum Foo {
+    Bar,
+    Baz
+}
+
+fn get_foo() -> Foo {
+    Foo::Bar
+}
+
+get_foo().match {
+    Foo::Bar => {},
+    Foo::Baz => panic!(),
+}
+```
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 855fb132fc8..810a870c35c 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -626,7 +626,10 @@ fn is_impl_trait(param: &hir::GenericParam<'_>) -> bool {
 ///
 /// See `lifetime_to_generic_param` in `rustc_ast_lowering` for more information.
 fn is_elided_lifetime(param: &hir::GenericParam<'_>) -> bool {
-    matches!(param.kind, hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided })
+    matches!(
+        param.kind,
+        hir::GenericParamKind::Lifetime { kind: hir::LifetimeParamKind::Elided(_) }
+    )
 }
 
 pub(crate) fn clean_generics<'tcx>(
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index 365d63d9657..977b4bb45b6 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -329,6 +329,7 @@ pub(crate) fn name_from_pat(p: &hir::Pat<'_>) -> Symbol {
             elts.iter().map(|p| name_from_pat(p).to_string()).collect::<Vec<String>>().join(", ")
         ),
         PatKind::Box(p) => return name_from_pat(&*p),
+        PatKind::Deref(p) => format!("deref!({})", name_from_pat(&*p)),
         PatKind::Ref(p, _) => return name_from_pat(&*p),
         PatKind::Lit(..) => {
             warn!(
diff --git a/src/llvm-project b/src/llvm-project
-Subproject 84f190a4abf58bbd5301c0fc831f7a96acea246
+Subproject 0af6c732ec6ca189cd7725e4a7d4290793046e8
diff --git a/src/tools/build-manifest/src/main.rs b/src/tools/build-manifest/src/main.rs
index eab9138b8fe..392a5a11967 100644
--- a/src/tools/build-manifest/src/main.rs
+++ b/src/tools/build-manifest/src/main.rs
@@ -126,6 +126,7 @@ static TARGETS: &[&str] = &[
     "riscv32i-unknown-none-elf",
     "riscv32im-risc0-zkvm-elf",
     "riscv32im-unknown-none-elf",
+    "riscv32ima-unknown-none-elf",
     "riscv32imc-unknown-none-elf",
     "riscv32imac-unknown-none-elf",
     "riscv32imafc-unknown-none-elf",
diff --git a/src/tools/clippy/.github/workflows/clippy.yml b/src/tools/clippy/.github/workflows/clippy.yml
index 603f91a910b..8179e3e65b5 100644
--- a/src/tools/clippy/.github/workflows/clippy.yml
+++ b/src/tools/clippy/.github/workflows/clippy.yml
@@ -26,6 +26,12 @@ env:
   NO_FMT_TEST: 1
   CARGO_INCREMENTAL: 0
 
+concurrency:
+  # For a given workflow, if we push to the same PR, cancel all previous builds on that PR.
+  # If the push is not attached to a PR, we will cancel all builds on the same branch.
+  group: "${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}"
+  cancel-in-progress: true
+
 jobs:
   base:
     # NOTE: If you modify this job, make sure you copy the changes to clippy_bors.yml
@@ -33,10 +39,6 @@ jobs:
 
     steps:
     # Setup
-    - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
-      with:
-        github_token: "${{ secrets.github_token }}"
-
     - name: Checkout
       uses: actions/checkout@v4
 
diff --git a/src/tools/clippy/.github/workflows/clippy_bors.yml b/src/tools/clippy/.github/workflows/clippy_bors.yml
index 0bc28c1f9d9..94515987eba 100644
--- a/src/tools/clippy/.github/workflows/clippy_bors.yml
+++ b/src/tools/clippy/.github/workflows/clippy_bors.yml
@@ -12,6 +12,11 @@ env:
   NO_FMT_TEST: 1
   CARGO_INCREMENTAL: 0
 
+concurrency:
+  # For a given workflow, if we push to the same branch, cancel all previous builds on that branch.
+  group: "${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}"
+  cancel-in-progress: true
+
 defaults:
   run:
     shell: bash
@@ -21,10 +26,6 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
-      with:
-        github_token: "${{ secrets.github_token }}"
-
     - name: Checkout
       uses: actions/checkout@v4
       with:
@@ -67,10 +68,6 @@ jobs:
     # NOTE: If you modify this job, make sure you copy the changes to clippy.yml
     steps:
     # Setup
-    - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
-      with:
-        github_token: "${{ secrets.github_token }}"
-
     - name: Checkout
       uses: actions/checkout@v4
 
@@ -131,10 +128,6 @@ jobs:
 
     steps:
      # Setup
-    - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
-      with:
-        github_token: "${{ secrets.github_token }}"
-
     - name: Checkout
       uses: actions/checkout@v4
 
@@ -155,10 +148,6 @@ jobs:
 
     steps:
     # Setup
-    - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
-      with:
-        github_token: "${{ secrets.github_token }}"
-
     - name: Checkout
       uses: actions/checkout@v4
 
@@ -211,10 +200,6 @@ jobs:
 
     steps:
     # Setup
-    - uses: rust-lang/simpleinfra/github-actions/cancel-outdated-builds@master
-      with:
-        github_token: "${{ secrets.github_token }}"
-
     - name: Checkout
       uses: actions/checkout@v4
 
diff --git a/src/tools/clippy/CHANGELOG.md b/src/tools/clippy/CHANGELOG.md
index d3b2c0a7bf6..76ef84a48b8 100644
--- a/src/tools/clippy/CHANGELOG.md
+++ b/src/tools/clippy/CHANGELOG.md
@@ -6,11 +6,65 @@ document.
 
 ## Unreleased / Beta / In Rust Nightly
 
-[a859e5cc...master](https://github.com/rust-lang/rust-clippy/compare/a859e5cc...master)
+[66c29b97...master](https://github.com/rust-lang/rust-clippy/compare/66c29b97...master)
+
+## Rust 1.77
+
+Current stable, released 2024-03-18
+
+[View all 93 merged pull requests](https://github.com/rust-lang/rust-clippy/pulls?q=merged%3A2023-12-16T18%3A20%3A00Z..2024-01-25T18%3A15%3A56Z+base%3Amaster)
+
+### New Lints
+
+* [`suspicious_open_options`]
+  [#11608](https://github.com/rust-lang/rust-clippy/pull/11608)
+* [`option_as_ref_cloned`]
+  [#12051](https://github.com/rust-lang/rust-clippy/pull/12051)
+* [`thread_local_initializer_can_be_made_const`]
+  [#12026](https://github.com/rust-lang/rust-clippy/pull/12026)
+* [`str_split_at_newline`]
+  [#11987](https://github.com/rust-lang/rust-clippy/pull/11987)
+* [`empty_enum_variants_with_brackets`]
+  [#12047](https://github.com/rust-lang/rust-clippy/pull/12047)
+* [`manual_is_variant_and`]
+  [#11865](https://github.com/rust-lang/rust-clippy/pull/11865)
+* [`pub_underscore_fields`]
+  [#10283](https://github.com/rust-lang/rust-clippy/pull/10283)
+* [`eager_transmute`]
+  [#11981](https://github.com/rust-lang/rust-clippy/pull/11981)
+* [`iter_filter_is_some`]
+  [#12004](https://github.com/rust-lang/rust/pull/12004)
+* [`iter_filter_is_ok`]
+  [#12004](https://github.com/rust-lang/rust/pull/12004)
+* [`result_filter_map`]
+  [#11869](https://github.com/rust-lang/rust-clippy/pull/11869)
+* [`unconditional_recursion`]
+  [#11938](https://github.com/rust-lang/rust-clippy/pull/11938)
+
+### Enhancements
+
+* [`multiple_crate_versions`]: Added the [`allowed-duplicate-crates`] configuration to allow specific crates
+  [#12179](https://github.com/rust-lang/rust-clippy/pull/12179)
+* [`single_call_fn`]: No longer ignores `#[allow]` attributes
+  [#12183](https://github.com/rust-lang/rust-clippy/pull/12183)
+* [`read_zero_byte_vec`]: Updated the heuristics used for linting
+  [#11766](https://github.com/rust-lang/rust-clippy/pull/11766)
+
+### ICE Fixes
+
+* [`unit_arg`]: No longer crashes when checking for const in nested bodies
+  [#11977](https://github.com/rust-lang/rust-clippy/pull/11977)
+* [`indexing_slicing`]: No longer crashes when the array index exceeds `usize`
+  [#12266](https://github.com/rust-lang/rust-clippy/pull/12266)
+
+### Others
+
+* Warnings about invalid fields inside `clippy.toml` files now include suggestions for existing fields
+  [#12180](https://github.com/rust-lang/rust-clippy/pull/12180)
 
 ## Rust 1.76
 
-Current stable, released 2024-02-08
+Released 2024-02-08
 
 [View all 85 merged pull requests](https://github.com/rust-lang/rust-clippy/pulls?q=merged%3A2023-11-02T20%3A23%3A40Z..2023-12-16T13%3A11%3A08Z+base%3Amaster)
 
@@ -5110,6 +5164,7 @@ Released 2018-09-13
 [`collection_is_never_read`]: https://rust-lang.github.io/rust-clippy/master/index.html#collection_is_never_read
 [`comparison_chain`]: https://rust-lang.github.io/rust-clippy/master/index.html#comparison_chain
 [`comparison_to_empty`]: https://rust-lang.github.io/rust-clippy/master/index.html#comparison_to_empty
+[`const_is_empty`]: https://rust-lang.github.io/rust-clippy/master/index.html#const_is_empty
 [`const_static_lifetime`]: https://rust-lang.github.io/rust-clippy/master/index.html#const_static_lifetime
 [`copy_iterator`]: https://rust-lang.github.io/rust-clippy/master/index.html#copy_iterator
 [`crate_in_macro_def`]: https://rust-lang.github.io/rust-clippy/master/index.html#crate_in_macro_def
@@ -5156,6 +5211,7 @@ Released 2018-09-13
 [`drop_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#drop_ref
 [`duplicate_mod`]: https://rust-lang.github.io/rust-clippy/master/index.html#duplicate_mod
 [`duplicate_underscore_argument`]: https://rust-lang.github.io/rust-clippy/master/index.html#duplicate_underscore_argument
+[`duplicated_attributes`]: https://rust-lang.github.io/rust-clippy/master/index.html#duplicated_attributes
 [`duration_subsec`]: https://rust-lang.github.io/rust-clippy/master/index.html#duration_subsec
 [`eager_transmute`]: https://rust-lang.github.io/rust-clippy/master/index.html#eager_transmute
 [`else_if_without_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#else_if_without_else
@@ -5279,6 +5335,7 @@ Released 2018-09-13
 [`int_plus_one`]: https://rust-lang.github.io/rust-clippy/master/index.html#int_plus_one
 [`integer_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#integer_arithmetic
 [`integer_division`]: https://rust-lang.github.io/rust-clippy/master/index.html#integer_division
+[`integer_division_remainder_used`]: https://rust-lang.github.io/rust-clippy/master/index.html#integer_division_remainder_used
 [`into_iter_on_array`]: https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_array
 [`into_iter_on_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
 [`into_iter_without_iter`]: https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_without_iter
@@ -5376,6 +5433,7 @@ Released 2018-09-13
 [`manual_swap`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_swap
 [`manual_try_fold`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_try_fold
 [`manual_unwrap_or`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_unwrap_or
+[`manual_unwrap_or_default`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_unwrap_or_default
 [`manual_while_let_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#manual_while_let_some
 [`many_single_char_names`]: https://rust-lang.github.io/rust-clippy/master/index.html#many_single_char_names
 [`map_clone`]: https://rust-lang.github.io/rust-clippy/master/index.html#map_clone
@@ -5813,6 +5871,7 @@ Released 2018-09-13
 [`zero_divided_by_zero`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_divided_by_zero
 [`zero_prefixed_literal`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_prefixed_literal
 [`zero_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_ptr
+[`zero_repeat_side_effects`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_repeat_side_effects
 [`zero_sized_map_values`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_sized_map_values
 [`zero_width_space`]: https://rust-lang.github.io/rust-clippy/master/index.html#zero_width_space
 [`zst_offset`]: https://rust-lang.github.io/rust-clippy/master/index.html#zst_offset
diff --git a/src/tools/clippy/Cargo.toml b/src/tools/clippy/Cargo.toml
index 5d1d0ce2c42..2b37b54c004 100644
--- a/src/tools/clippy/Cargo.toml
+++ b/src/tools/clippy/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "clippy"
-version = "0.1.78"
+version = "0.1.79"
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
 repository = "https://github.com/rust-lang/rust-clippy"
 readme = "README.md"
@@ -24,7 +24,7 @@ path = "src/driver.rs"
 clippy_config = { path = "clippy_config" }
 clippy_lints = { path = "clippy_lints" }
 rustc_tools_util = "0.3.0"
-tempfile = { version = "3.2", optional = true }
+tempfile = { version = "3.3", optional = true }
 termize = "0.1"
 color-print = "0.3.4"
 anstream = "0.6.0"
@@ -32,18 +32,18 @@ anstream = "0.6.0"
 [dev-dependencies]
 ui_test = "0.22.2"
 tester = "0.9"
-regex = "1.5"
+regex = "1.5.5"
 toml = "0.7.3"
 walkdir = "2.3"
 # This is used by the `collect-metadata` alias.
-filetime = "0.2"
+filetime = "0.2.9"
 itertools = "0.12"
 
 # UI test dependencies
 clippy_utils = { path = "clippy_utils" }
 if_chain = "1.0"
-quote = "1.0"
-serde = { version = "1.0.125", features = ["derive"] }
+quote = "1.0.25"
+serde = { version = "1.0.145", features = ["derive"] }
 syn = { version = "2.0", features = ["full"] }
 futures = "0.3"
 parking_lot = "0.12"
diff --git a/src/tools/clippy/book/src/development/macro_expansions.md b/src/tools/clippy/book/src/development/macro_expansions.md
index aecca9ef72e..125b6c4bc5b 100644
--- a/src/tools/clippy/book/src/development/macro_expansions.md
+++ b/src/tools/clippy/book/src/development/macro_expansions.md
@@ -52,7 +52,7 @@ if expr.span.from_expansion() {
 
 ### `Span.ctxt` method
 
-The `span`'s context, given by the method [`ctxt`] and returning [SpanContext],
+The `span`'s context, given by the method [`ctxt`] and returning [SyntaxContext],
 represents if the span is from a macro expansion and, if it is, which
 macro call expanded this span.
 
@@ -155,4 +155,4 @@ if in_external_macro(cx.sess(), foo_span) {
 [`from_expansion`]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/struct.Span.html#method.from_expansion
 [`in_external_macro`]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_middle/lint/fn.in_external_macro.html
 [Span]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/struct.Span.html
-[SpanContext]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/hygiene/struct.SyntaxContext.html
+[SyntaxContext]: https://doc.rust-lang.org/stable/nightly-rustc/rustc_span/hygiene/struct.SyntaxContext.html
diff --git a/src/tools/clippy/book/src/lint_configuration.md b/src/tools/clippy/book/src/lint_configuration.md
index a985346b3c0..a9234899746 100644
--- a/src/tools/clippy/book/src/lint_configuration.md
+++ b/src/tools/clippy/book/src/lint_configuration.md
@@ -602,6 +602,7 @@ The minimum rust version that the project supports. Defaults to the `rust-versio
 **Affected lints:**
 * [`almost_complete_range`](https://rust-lang.github.io/rust-clippy/master/index.html#almost_complete_range)
 * [`approx_constant`](https://rust-lang.github.io/rust-clippy/master/index.html#approx_constant)
+* [`assigning_clones`](https://rust-lang.github.io/rust-clippy/master/index.html#assigning_clones)
 * [`borrow_as_ptr`](https://rust-lang.github.io/rust-clippy/master/index.html#borrow_as_ptr)
 * [`cast_abs_to_unsigned`](https://rust-lang.github.io/rust-clippy/master/index.html#cast_abs_to_unsigned)
 * [`checked_conversions`](https://rust-lang.github.io/rust-clippy/master/index.html#checked_conversions)
diff --git a/src/tools/clippy/clippy.toml b/src/tools/clippy/clippy.toml
index 8c405ac6a4e..62ed55beb1f 100644
--- a/src/tools/clippy/clippy.toml
+++ b/src/tools/clippy/clippy.toml
@@ -1,7 +1,10 @@
 avoid-breaking-exported-api = false
 
-# use the various `span_lint_*` methods instead, which also add a link to the docs
-disallowed-methods = [
-    "rustc_lint::context::LintContext::span_lint",
-    "rustc_middle::ty::context::TyCtxt::node_span_lint"
-]
+[[disallowed-methods]]
+path = "rustc_lint::context::LintContext::span_lint"
+reason = "this function does not add a link to our documentation, please use the `clippy_utils::diagnostics::span_lint*` functions instead"
+
+
+[[disallowed-methods]]
+path = "rustc_middle::ty::context::TyCtxt::node_span_lint"
+reason = "this function does not add a link to our documentation, please use the `clippy_utils::diagnostics::span_lint_hir*` functions instead"
diff --git a/src/tools/clippy/clippy_config/Cargo.toml b/src/tools/clippy/clippy_config/Cargo.toml
index 2edc5ed592c..8ba2ab56625 100644
--- a/src/tools/clippy/clippy_config/Cargo.toml
+++ b/src/tools/clippy/clippy_config/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "clippy_config"
-version = "0.1.78"
+version = "0.1.79"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
diff --git a/src/tools/clippy/clippy_config/src/conf.rs b/src/tools/clippy/clippy_config/src/conf.rs
index 673b6328b39..3218fe7f456 100644
--- a/src/tools/clippy/clippy_config/src/conf.rs
+++ b/src/tools/clippy/clippy_config/src/conf.rs
@@ -262,7 +262,7 @@ define_Conf! {
     ///
     /// Suppress lints whenever the suggested change would cause breakage for other crates.
     (avoid_breaking_exported_api: bool = true),
-    /// Lint: MANUAL_SPLIT_ONCE, MANUAL_STR_REPEAT, CLONED_INSTEAD_OF_COPIED, REDUNDANT_FIELD_NAMES, OPTION_MAP_UNWRAP_OR, REDUNDANT_STATIC_LIFETIMES, FILTER_MAP_NEXT, CHECKED_CONVERSIONS, MANUAL_RANGE_CONTAINS, USE_SELF, MEM_REPLACE_WITH_DEFAULT, MANUAL_NON_EXHAUSTIVE, OPTION_AS_REF_DEREF, MAP_UNWRAP_OR, MATCH_LIKE_MATCHES_MACRO, MANUAL_STRIP, MISSING_CONST_FOR_FN, UNNESTED_OR_PATTERNS, FROM_OVER_INTO, PTR_AS_PTR, IF_THEN_SOME_ELSE_NONE, APPROX_CONSTANT, DEPRECATED_CFG_ATTR, INDEX_REFUTABLE_SLICE, MAP_CLONE, BORROW_AS_PTR, MANUAL_BITS, ERR_EXPECT, CAST_ABS_TO_UNSIGNED, UNINLINED_FORMAT_ARGS, MANUAL_CLAMP, MANUAL_LET_ELSE, UNCHECKED_DURATION_SUBTRACTION, COLLAPSIBLE_STR_REPLACE, SEEK_FROM_CURRENT, SEEK_REWIND, UNNECESSARY_LAZY_EVALUATIONS, TRANSMUTE_PTR_TO_REF, ALMOST_COMPLETE_RANGE, NEEDLESS_BORROW, DERIVABLE_IMPLS, MANUAL_IS_ASCII_CHECK, MANUAL_REM_EUCLID, MANUAL_RETAIN, TYPE_REPETITION_IN_BOUNDS, TUPLE_ARRAY_CONVERSIONS, MANUAL_TRY_FOLD, MANUAL_HASH_ONE, ITER_KV_MAP, MANUAL_C_STR_LITERALS.
+    /// Lint: MANUAL_SPLIT_ONCE, MANUAL_STR_REPEAT, CLONED_INSTEAD_OF_COPIED, REDUNDANT_FIELD_NAMES, OPTION_MAP_UNWRAP_OR, REDUNDANT_STATIC_LIFETIMES, FILTER_MAP_NEXT, CHECKED_CONVERSIONS, MANUAL_RANGE_CONTAINS, USE_SELF, MEM_REPLACE_WITH_DEFAULT, MANUAL_NON_EXHAUSTIVE, OPTION_AS_REF_DEREF, MAP_UNWRAP_OR, MATCH_LIKE_MATCHES_MACRO, MANUAL_STRIP, MISSING_CONST_FOR_FN, UNNESTED_OR_PATTERNS, FROM_OVER_INTO, PTR_AS_PTR, IF_THEN_SOME_ELSE_NONE, APPROX_CONSTANT, DEPRECATED_CFG_ATTR, INDEX_REFUTABLE_SLICE, MAP_CLONE, BORROW_AS_PTR, MANUAL_BITS, ERR_EXPECT, CAST_ABS_TO_UNSIGNED, UNINLINED_FORMAT_ARGS, MANUAL_CLAMP, MANUAL_LET_ELSE, UNCHECKED_DURATION_SUBTRACTION, COLLAPSIBLE_STR_REPLACE, SEEK_FROM_CURRENT, SEEK_REWIND, UNNECESSARY_LAZY_EVALUATIONS, TRANSMUTE_PTR_TO_REF, ALMOST_COMPLETE_RANGE, NEEDLESS_BORROW, DERIVABLE_IMPLS, MANUAL_IS_ASCII_CHECK, MANUAL_REM_EUCLID, MANUAL_RETAIN, TYPE_REPETITION_IN_BOUNDS, TUPLE_ARRAY_CONVERSIONS, MANUAL_TRY_FOLD, MANUAL_HASH_ONE, ITER_KV_MAP, MANUAL_C_STR_LITERALS, ASSIGNING_CLONES.
     ///
     /// The minimum rust version that the project supports. Defaults to the `rust-version` field in `Cargo.toml`
     #[default_text = ""]
diff --git a/src/tools/clippy/clippy_config/src/msrvs.rs b/src/tools/clippy/clippy_config/src/msrvs.rs
index a8a32f7ed20..bf4da5f14fe 100644
--- a/src/tools/clippy/clippy_config/src/msrvs.rs
+++ b/src/tools/clippy/clippy_config/src/msrvs.rs
@@ -23,6 +23,7 @@ msrv_aliases! {
     1,70,0 { OPTION_RESULT_IS_VARIANT_AND, BINARY_HEAP_RETAIN }
     1,68,0 { PATH_MAIN_SEPARATOR_STR }
     1,65,0 { LET_ELSE, POINTER_CAST_CONSTNESS }
+    1,63,0 { ASSIGNING_CLONES }
     1,62,0 { BOOL_THEN_SOME, DEFAULT_ENUM_ATTRIBUTE }
     1,59,0 { THREAD_LOCAL_INITIALIZER_CAN_BE_MADE_CONST }
     1,58,0 { FORMAT_ARGS_CAPTURE, PATTERN_TRAIT_CHAR_ARRAY }
diff --git a/src/tools/clippy/clippy_dev/src/update_lints.rs b/src/tools/clippy/clippy_dev/src/update_lints.rs
index 2222abff7ad..76ae26dddf4 100644
--- a/src/tools/clippy/clippy_dev/src/update_lints.rs
+++ b/src/tools/clippy/clippy_dev/src/update_lints.rs
@@ -689,6 +689,8 @@ fn gen_deprecated_lints_test(lints: &[DeprecatedLint]) -> String {
 fn gen_renamed_lints_test(lints: &[RenamedLint]) -> String {
     let mut seen_lints = HashSet::new();
     let mut res: String = GENERATED_FILE_COMMENT.into();
+
+    res.push_str("#![allow(clippy::duplicated_attributes)]\n");
     for lint in lints {
         if seen_lints.insert(&lint.new_name) {
             writeln!(res, "#![allow({})]", lint.new_name).unwrap();
diff --git a/src/tools/clippy/clippy_lints/Cargo.toml b/src/tools/clippy/clippy_lints/Cargo.toml
index 6ae089b3e03..1d954607eee 100644
--- a/src/tools/clippy/clippy_lints/Cargo.toml
+++ b/src/tools/clippy/clippy_lints/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "clippy_lints"
-version = "0.1.78"
+version = "0.1.79"
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
 repository = "https://github.com/rust-lang/rust-clippy"
 readme = "README.md"
diff --git a/src/tools/clippy/clippy_lints/src/assigning_clones.rs b/src/tools/clippy/clippy_lints/src/assigning_clones.rs
index b1c552c7a8d..88d9f762a87 100644
--- a/src/tools/clippy/clippy_lints/src/assigning_clones.rs
+++ b/src/tools/clippy/clippy_lints/src/assigning_clones.rs
@@ -1,3 +1,4 @@
+use clippy_config::msrvs::{self, Msrv};
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::macros::HirNode;
 use clippy_utils::sugg::Sugg;
@@ -6,7 +7,7 @@ use rustc_errors::Applicability;
 use rustc_hir::{self as hir, Expr, ExprKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self, Instance, Mutability};
-use rustc_session::declare_lint_pass;
+use rustc_session::impl_lint_pass;
 use rustc_span::def_id::DefId;
 use rustc_span::symbol::sym;
 use rustc_span::ExpnKind;
@@ -49,7 +50,19 @@ declare_clippy_lint! {
     perf,
     "assigning the result of cloning may be inefficient"
 }
-declare_lint_pass!(AssigningClones => [ASSIGNING_CLONES]);
+
+pub struct AssigningClones {
+    msrv: Msrv,
+}
+
+impl AssigningClones {
+    #[must_use]
+    pub fn new(msrv: Msrv) -> Self {
+        Self { msrv }
+    }
+}
+
+impl_lint_pass!(AssigningClones => [ASSIGNING_CLONES]);
 
 impl<'tcx> LateLintPass<'tcx> for AssigningClones {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, assign_expr: &'tcx hir::Expr<'_>) {
@@ -68,10 +81,12 @@ impl<'tcx> LateLintPass<'tcx> for AssigningClones {
             return;
         };
 
-        if is_ok_to_suggest(cx, lhs, &call) {
+        if is_ok_to_suggest(cx, lhs, &call, &self.msrv) {
             suggest(cx, assign_expr, lhs, &call);
         }
     }
+
+    extract_msrv_attr!(LateContext);
 }
 
 // Try to resolve the call to `Clone::clone` or `ToOwned::to_owned`.
@@ -135,7 +150,13 @@ fn extract_call<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> Option<
 
 // Return true if we find that the called method has a custom implementation and isn't derived or
 // provided by default by the corresponding trait.
-fn is_ok_to_suggest<'tcx>(cx: &LateContext<'tcx>, lhs: &Expr<'tcx>, call: &CallCandidate<'tcx>) -> bool {
+fn is_ok_to_suggest<'tcx>(cx: &LateContext<'tcx>, lhs: &Expr<'tcx>, call: &CallCandidate<'tcx>, msrv: &Msrv) -> bool {
+    // For calls to .to_owned we suggest using .clone_into(), which was only stablilized in 1.63.
+    // If the current MSRV is below that, don't suggest the lint.
+    if !msrv.meets(msrvs::ASSIGNING_CLONES) && matches!(call.target, TargetTrait::ToOwned) {
+        return false;
+    }
+
     // If the left-hand side is a local variable, it might be uninitialized at this point.
     // In that case we do not want to suggest the lint.
     if let Some(local) = path_to_local(lhs) {
diff --git a/src/tools/clippy/clippy_lints/src/attrs/duplicated_attributes.rs b/src/tools/clippy/clippy_lints/src/attrs/duplicated_attributes.rs
new file mode 100644
index 00000000000..3c5ac597fd5
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/attrs/duplicated_attributes.rs
@@ -0,0 +1,64 @@
+use super::DUPLICATED_ATTRIBUTES;
+use clippy_utils::diagnostics::span_lint_and_then;
+use rustc_ast::{Attribute, MetaItem};
+use rustc_data_structures::fx::FxHashMap;
+use rustc_lint::EarlyContext;
+use rustc_span::{sym, Span};
+use std::collections::hash_map::Entry;
+
+fn emit_if_duplicated(
+    cx: &EarlyContext<'_>,
+    attr: &MetaItem,
+    attr_paths: &mut FxHashMap<String, Span>,
+    complete_path: String,
+) {
+    match attr_paths.entry(complete_path) {
+        Entry::Vacant(v) => {
+            v.insert(attr.span);
+        },
+        Entry::Occupied(o) => {
+            span_lint_and_then(cx, DUPLICATED_ATTRIBUTES, attr.span, "duplicated attribute", |diag| {
+                diag.span_note(*o.get(), "first defined here");
+                diag.span_help(attr.span, "remove this attribute");
+            });
+        },
+    }
+}
+
+fn check_duplicated_attr(
+    cx: &EarlyContext<'_>,
+    attr: &MetaItem,
+    attr_paths: &mut FxHashMap<String, Span>,
+    parent: &mut Vec<String>,
+) {
+    let Some(ident) = attr.ident() else { return };
+    let name = ident.name;
+    if name == sym::doc || name == sym::cfg_attr {
+        // FIXME: Would be nice to handle `cfg_attr` as well. Only problem is to check that cfg
+        // conditions are the same.
+        return;
+    }
+    if let Some(value) = attr.value_str() {
+        emit_if_duplicated(cx, attr, attr_paths, format!("{}:{name}={value}", parent.join(":")));
+    } else if let Some(sub_attrs) = attr.meta_item_list() {
+        parent.push(name.as_str().to_string());
+        for sub_attr in sub_attrs {
+            if let Some(meta) = sub_attr.meta_item() {
+                check_duplicated_attr(cx, meta, attr_paths, parent);
+            }
+        }
+        parent.pop();
+    } else {
+        emit_if_duplicated(cx, attr, attr_paths, format!("{}:{name}", parent.join(":")));
+    }
+}
+
+pub fn check(cx: &EarlyContext<'_>, attrs: &[Attribute]) {
+    let mut attr_paths = FxHashMap::default();
+
+    for attr in attrs {
+        if let Some(meta) = attr.meta() {
+            check_duplicated_attr(cx, &meta, &mut attr_paths, &mut Vec::new());
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/attrs/mod.rs b/src/tools/clippy/clippy_lints/src/attrs/mod.rs
index c4c65d3248a..675c428948f 100644
--- a/src/tools/clippy/clippy_lints/src/attrs/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/attrs/mod.rs
@@ -4,6 +4,7 @@ mod allow_attributes_without_reason;
 mod blanket_clippy_restriction_lints;
 mod deprecated_cfg_attr;
 mod deprecated_semver;
+mod duplicated_attributes;
 mod empty_line_after;
 mod inline_always;
 mod maybe_misused_cfg;
@@ -16,7 +17,7 @@ mod useless_attribute;
 mod utils;
 
 use clippy_config::msrvs::Msrv;
-use rustc_ast::{Attribute, MetaItemKind, NestedMetaItem};
+use rustc_ast::{Attribute, Crate, MetaItemKind, NestedMetaItem};
 use rustc_hir::{ImplItem, Item, ItemKind, TraitItem};
 use rustc_lint::{EarlyContext, EarlyLintPass, LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, impl_lint_pass};
@@ -489,6 +490,32 @@ declare_clippy_lint! {
     "item has both inner and outer attributes"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for attributes that appear two or more times.
+    ///
+    /// ### Why is this bad?
+    /// Repeating an attribute on the same item (or globally on the same crate)
+    /// is unnecessary and doesn't have an effect.
+    ///
+    /// ### Example
+    /// ```no_run
+    /// #[allow(dead_code)]
+    /// #[allow(dead_code)]
+    /// fn foo() {}
+    /// ```
+    ///
+    /// Use instead:
+    /// ```no_run
+    /// #[allow(dead_code)]
+    /// fn foo() {}
+    /// ```
+    #[clippy::version = "1.78.0"]
+    pub DUPLICATED_ATTRIBUTES,
+    suspicious,
+    "duplicated attribute"
+}
+
 declare_lint_pass!(Attributes => [
     ALLOW_ATTRIBUTES_WITHOUT_REASON,
     INLINE_ALWAYS,
@@ -568,12 +595,18 @@ impl_lint_pass!(EarlyAttributes => [
     DEPRECATED_CLIPPY_CFG_ATTR,
     UNNECESSARY_CLIPPY_CFG,
     MIXED_ATTRIBUTES_STYLE,
+    DUPLICATED_ATTRIBUTES,
 ]);
 
 impl EarlyLintPass for EarlyAttributes {
+    fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &Crate) {
+        duplicated_attributes::check(cx, &krate.attrs);
+    }
+
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &rustc_ast::Item) {
         empty_line_after::check(cx, item);
         mixed_attributes_style::check(cx, item);
+        duplicated_attributes::check(cx, &item.attrs);
     }
 
     fn check_attribute(&mut self, cx: &EarlyContext<'_>, attr: &Attribute) {
diff --git a/src/tools/clippy/clippy_lints/src/box_default.rs b/src/tools/clippy/clippy_lints/src/box_default.rs
index 779ae03c464..66206d1a059 100644
--- a/src/tools/clippy/clippy_lints/src/box_default.rs
+++ b/src/tools/clippy/clippy_lints/src/box_default.rs
@@ -70,7 +70,9 @@ impl LateLintPass<'_> for BoxDefault {
                 "try",
                 if is_plain_default(cx, arg_path) || given_type(cx, expr) {
                     "Box::default()".into()
-                } else if let Some(arg_ty) = cx.typeck_results().expr_ty(arg).make_suggestable(cx.tcx, true) {
+                } else if let Some(arg_ty) =
+                    cx.typeck_results().expr_ty(arg).make_suggestable(cx.tcx, true, None)
+                {
                     // Check if we can copy from the source expression in the replacement.
                     // We need the call to have no argument (see `explicit_default_type`).
                     if inner_call_args.is_empty()
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_lossless.rs b/src/tools/clippy/clippy_lints/src/casts/cast_lossless.rs
index fe2455f4b23..86f4332d05a 100644
--- a/src/tools/clippy/clippy_lints/src/casts/cast_lossless.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_lossless.rs
@@ -1,12 +1,12 @@
 use clippy_config::msrvs::{self, Msrv};
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::in_constant;
-use clippy_utils::source::snippet_opt;
+use clippy_utils::source::{snippet_opt, snippet_with_applicability};
 use clippy_utils::ty::is_isize_or_usize;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
+use rustc_hir::{Expr, ExprKind, QPath, TyKind};
 use rustc_lint::LateContext;
-use rustc_middle::ty::{self, FloatTy, Ty};
+use rustc_middle::ty::{self, FloatTy, Ty, UintTy};
 
 use super::{utils, CAST_LOSSLESS};
 
@@ -16,6 +16,7 @@ pub(super) fn check(
     cast_op: &Expr<'_>,
     cast_from: Ty<'_>,
     cast_to: Ty<'_>,
+    cast_to_hir: &rustc_hir::Ty<'_>,
     msrv: &Msrv,
 ) {
     if !should_lint(cx, expr, cast_from, cast_to, msrv) {
@@ -24,11 +25,11 @@ pub(super) fn check(
 
     // The suggestion is to use a function call, so if the original expression
     // has parens on the outside, they are no longer needed.
-    let mut applicability = Applicability::MachineApplicable;
+    let mut app = Applicability::MachineApplicable;
     let opt = snippet_opt(cx, cast_op.span.source_callsite());
     let sugg = opt.as_ref().map_or_else(
         || {
-            applicability = Applicability::HasPlaceholders;
+            app = Applicability::HasPlaceholders;
             ".."
         },
         |snip| {
@@ -40,10 +41,27 @@ pub(super) fn check(
         },
     );
 
+    // Display the type alias instead of the aliased type. Fixes #11285
+    //
+    // FIXME: Once `lazy_type_alias` is stabilized(?) we should use `rustc_middle` types instead,
+    // this will allow us to display the right type with `cast_from` as well.
+    let cast_to_fmt = if let TyKind::Path(QPath::Resolved(None, path)) = cast_to_hir.kind
+        // It's a bit annoying but the turbofish is optional for types. A type in an `as` cast
+        // shouldn't have these if they're primitives, which are the only things we deal with.
+        //
+        // This could be removed for performance if this check is determined to have a pretty major
+        // effect.
+        && path.segments.iter().all(|segment| segment.args.is_none())
+    {
+        snippet_with_applicability(cx, cast_to_hir.span, "..", &mut app)
+    } else {
+        cast_to.to_string().into()
+    };
+
     let message = if cast_from.is_bool() {
-        format!("casting `{cast_from:}` to `{cast_to:}` is more cleanly stated with `{cast_to:}::from(_)`")
+        format!("casting `{cast_from}` to `{cast_to_fmt}` is more cleanly stated with `{cast_to_fmt}::from(_)`")
     } else {
-        format!("casting `{cast_from}` to `{cast_to}` may become silently lossy if you later change the type")
+        format!("casting `{cast_from}` to `{cast_to_fmt}` may become silently lossy if you later change the type")
     };
 
     span_lint_and_sugg(
@@ -52,14 +70,17 @@ pub(super) fn check(
         expr.span,
         &message,
         "try",
-        format!("{cast_to}::from({sugg})"),
-        applicability,
+        format!("{cast_to_fmt}::from({sugg})"),
+        app,
     );
 }
 
 fn should_lint(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>, msrv: &Msrv) -> bool {
     // Do not suggest using From in consts/statics until it is valid to do so (see #2267).
-    if in_constant(cx, expr.hir_id) {
+    //
+    // If destination is u128, do not lint because source type cannot be larger
+    // If source is bool, still lint due to the lint message differing (refers to style)
+    if in_constant(cx, expr.hir_id) || (!cast_from.is_bool() && matches!(cast_to.kind(), ty::Uint(UintTy::U128))) {
         return false;
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/casts/mod.rs b/src/tools/clippy/clippy_lints/src/casts/mod.rs
index 14f2f4a7f59..063aab28238 100644
--- a/src/tools/clippy/clippy_lints/src/casts/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/casts/mod.rs
@@ -791,7 +791,7 @@ impl<'tcx> LateLintPass<'tcx> for Casts {
                     cast_abs_to_unsigned::check(cx, expr, cast_expr, cast_from, cast_to, &self.msrv);
                     cast_nan_to_int::check(cx, expr, cast_expr, cast_from, cast_to);
                 }
-                cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to, &self.msrv);
+                cast_lossless::check(cx, expr, cast_expr, cast_from, cast_to, cast_to_hir, &self.msrv);
                 cast_enum_constructor::check(cx, expr, cast_expr, cast_from);
             }
 
diff --git a/src/tools/clippy/clippy_lints/src/dbg_macro.rs b/src/tools/clippy/clippy_lints/src/dbg_macro.rs
index ec66556cebf..e2296767431 100644
--- a/src/tools/clippy/clippy_lints/src/dbg_macro.rs
+++ b/src/tools/clippy/clippy_lints/src/dbg_macro.rs
@@ -1,12 +1,14 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::macros::root_macro_call_first_node;
+use clippy_utils::macros::{macro_backtrace, MacroCall};
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::{is_in_cfg_test, is_in_test_function};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, Node};
+use rustc_hir::{Expr, ExprKind, HirId, Node};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
 use rustc_session::impl_lint_pass;
-use rustc_span::sym;
+use rustc_span::{sym, Span, SyntaxContext};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -31,31 +33,38 @@ declare_clippy_lint! {
     "`dbg!` macro is intended as a debugging tool"
 }
 
-#[derive(Copy, Clone)]
+#[derive(Clone)]
 pub struct DbgMacro {
     allow_dbg_in_tests: bool,
+    /// Tracks the `dbg!` macro callsites that are already checked.
+    checked_dbg_call_site: FxHashSet<Span>,
+    /// Tracks the previous `SyntaxContext`, to avoid walking the same context chain.
+    prev_ctxt: SyntaxContext,
 }
 
 impl_lint_pass!(DbgMacro => [DBG_MACRO]);
 
 impl DbgMacro {
     pub fn new(allow_dbg_in_tests: bool) -> Self {
-        DbgMacro { allow_dbg_in_tests }
+        DbgMacro {
+            allow_dbg_in_tests,
+            checked_dbg_call_site: FxHashSet::default(),
+            prev_ctxt: SyntaxContext::root(),
+        }
     }
 }
 
 impl LateLintPass<'_> for DbgMacro {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
-        let Some(macro_call) = root_macro_call_first_node(cx, expr) else {
-            return;
-        };
-        if cx.tcx.is_diagnostic_item(sym::dbg_macro, macro_call.def_id) {
+        let cur_syntax_ctxt = expr.span.ctxt();
+
+        if cur_syntax_ctxt != self.prev_ctxt &&
+            let Some(macro_call) = first_dbg_macro_in_expansion(cx, expr.span) &&
+            !in_external_macro(cx.sess(), macro_call.span) &&
+            self.checked_dbg_call_site.insert(macro_call.span) &&
             // allows `dbg!` in test code if allow-dbg-in-test is set to true in clippy.toml
-            if self.allow_dbg_in_tests
-                && (is_in_test_function(cx.tcx, expr.hir_id) || is_in_cfg_test(cx.tcx, expr.hir_id))
-            {
-                return;
-            }
+            !(self.allow_dbg_in_tests && is_in_test(cx, expr.hir_id))
+        {
             let mut applicability = Applicability::MachineApplicable;
 
             let (sugg_span, suggestion) = match expr.peel_drop_temps().kind {
@@ -101,6 +110,8 @@ impl LateLintPass<'_> for DbgMacro {
                 _ => return,
             };
 
+            self.prev_ctxt = cur_syntax_ctxt;
+
             span_lint_and_sugg(
                 cx,
                 DBG_MACRO,
@@ -112,4 +123,16 @@ impl LateLintPass<'_> for DbgMacro {
             );
         }
     }
+
+    fn check_crate_post(&mut self, _: &LateContext<'_>) {
+        self.checked_dbg_call_site = FxHashSet::default();
+    }
+}
+
+fn is_in_test(cx: &LateContext<'_>, hir_id: HirId) -> bool {
+    is_in_test_function(cx.tcx, hir_id) || is_in_cfg_test(cx.tcx, hir_id)
+}
+
+fn first_dbg_macro_in_expansion(cx: &LateContext<'_>, span: Span) -> Option<MacroCall> {
+    macro_backtrace(span).find(|mc| cx.tcx.is_diagnostic_item(sym::dbg_macro, mc.def_id))
 }
diff --git a/src/tools/clippy/clippy_lints/src/declared_lints.rs b/src/tools/clippy/clippy_lints/src/declared_lints.rs
index 2b324f5f96e..c8e148598a2 100644
--- a/src/tools/clippy/clippy_lints/src/declared_lints.rs
+++ b/src/tools/clippy/clippy_lints/src/declared_lints.rs
@@ -54,6 +54,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::attrs::DEPRECATED_CFG_ATTR_INFO,
     crate::attrs::DEPRECATED_CLIPPY_CFG_ATTR_INFO,
     crate::attrs::DEPRECATED_SEMVER_INFO,
+    crate::attrs::DUPLICATED_ATTRIBUTES_INFO,
     crate::attrs::EMPTY_LINE_AFTER_DOC_COMMENTS_INFO,
     crate::attrs::EMPTY_LINE_AFTER_OUTER_ATTR_INFO,
     crate::attrs::INLINE_ALWAYS_INFO,
@@ -235,6 +236,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::instant_subtraction::MANUAL_INSTANT_ELAPSED_INFO,
     crate::instant_subtraction::UNCHECKED_DURATION_SUBTRACTION_INFO,
     crate::int_plus_one::INT_PLUS_ONE_INFO,
+    crate::integer_division_remainder_used::INTEGER_DIVISION_REMAINDER_USED_INFO,
     crate::invalid_upcast_comparisons::INVALID_UPCAST_COMPARISONS_INFO,
     crate::item_name_repetitions::ENUM_VARIANT_NAMES_INFO,
     crate::item_name_repetitions::MODULE_INCEPTION_INFO,
@@ -310,6 +312,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::manual_slice_size_calculation::MANUAL_SLICE_SIZE_CALCULATION_INFO,
     crate::manual_string_new::MANUAL_STRING_NEW_INFO,
     crate::manual_strip::MANUAL_STRIP_INFO,
+    crate::manual_unwrap_or_default::MANUAL_UNWRAP_OR_DEFAULT_INFO,
     crate::map_unit_fn::OPTION_MAP_UNIT_FN_INFO,
     crate::map_unit_fn::RESULT_MAP_UNIT_FN_INFO,
     crate::match_result_ok::MATCH_RESULT_OK_INFO,
@@ -353,6 +356,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::methods::CLONE_ON_COPY_INFO,
     crate::methods::CLONE_ON_REF_PTR_INFO,
     crate::methods::COLLAPSIBLE_STR_REPLACE_INFO,
+    crate::methods::CONST_IS_EMPTY_INFO,
     crate::methods::DRAIN_COLLECT_INFO,
     crate::methods::ERR_EXPECT_INFO,
     crate::methods::EXPECT_FUN_CALL_INFO,
@@ -750,5 +754,6 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[
     crate::write::WRITE_LITERAL_INFO,
     crate::write::WRITE_WITH_NEWLINE_INFO,
     crate::zero_div_zero::ZERO_DIVIDED_BY_ZERO_INFO,
+    crate::zero_repeat_side_effects::ZERO_REPEAT_SIDE_EFFECTS_INFO,
     crate::zero_sized_map_values::ZERO_SIZED_MAP_VALUES_INFO,
 ];
diff --git a/src/tools/clippy/clippy_lints/src/doc/markdown.rs b/src/tools/clippy/clippy_lints/src/doc/markdown.rs
index d2f14756591..1add02af310 100644
--- a/src/tools/clippy/clippy_lints/src/doc/markdown.rs
+++ b/src/tools/clippy/clippy_lints/src/doc/markdown.rs
@@ -8,7 +8,14 @@ use url::Url;
 
 use crate::doc::DOC_MARKDOWN;
 
-pub fn check(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, text: &str, span: Span, code_level: isize) {
+pub fn check(
+    cx: &LateContext<'_>,
+    valid_idents: &FxHashSet<String>,
+    text: &str,
+    span: Span,
+    code_level: isize,
+    blockquote_level: isize,
+) {
     for orig_word in text.split(|c: char| c.is_whitespace() || c == '\'') {
         // Trim punctuation as in `some comment (see foo::bar).`
         //                                                   ^^
@@ -46,11 +53,11 @@ pub fn check(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, text: &str,
             span.parent(),
         );
 
-        check_word(cx, word, span, code_level);
+        check_word(cx, word, span, code_level, blockquote_level);
     }
 }
 
-fn check_word(cx: &LateContext<'_>, word: &str, span: Span, code_level: isize) {
+fn check_word(cx: &LateContext<'_>, word: &str, span: Span, code_level: isize, blockquote_level: isize) {
     /// Checks if a string is upper-camel-case, i.e., starts with an uppercase and
     /// contains at least two uppercase letters (`Clippy` is ok) and one lower-case
     /// letter (`NASA` is ok).
@@ -97,7 +104,9 @@ fn check_word(cx: &LateContext<'_>, word: &str, span: Span, code_level: isize) {
     }
 
     // We assume that mixed-case words are not meant to be put inside backticks. (Issue #2343)
-    if code_level > 0 || (has_underscore(word) && has_hyphen(word)) {
+    //
+    // We also assume that backticks are not necessary if inside a quote. (Issue #10262)
+    if code_level > 0 || blockquote_level > 0 || (has_underscore(word) && has_hyphen(word)) {
         return;
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/doc/mod.rs b/src/tools/clippy/clippy_lints/src/doc/mod.rs
index 003d26b7b89..b135e4e3577 100644
--- a/src/tools/clippy/clippy_lints/src/doc/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/doc/mod.rs
@@ -7,14 +7,14 @@ use clippy_utils::{is_entrypoint_fn, method_chain_args};
 use pulldown_cmark::Event::{
     Code, End, FootnoteReference, HardBreak, Html, Rule, SoftBreak, Start, TaskListMarker, Text,
 };
-use pulldown_cmark::Tag::{CodeBlock, Heading, Item, Link, Paragraph};
+use pulldown_cmark::Tag::{BlockQuote, CodeBlock, Heading, Item, Link, Paragraph};
 use pulldown_cmark::{BrokenLink, CodeBlockKind, CowStr, Options};
 use rustc_ast::ast::Attribute;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{AnonConst, Expr};
-use rustc_lint::{LateContext, LateLintPass};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
@@ -538,7 +538,16 @@ fn check_attrs(cx: &LateContext<'_>, valid_idents: &FxHashSet<String>, attrs: &[
 
     suspicious_doc_comments::check(cx, attrs);
 
-    let (fragments, _) = attrs_to_doc_fragments(attrs.iter().map(|attr| (attr, None)), true);
+    let (fragments, _) = attrs_to_doc_fragments(
+        attrs.iter().filter_map(|attr| {
+            if in_external_macro(cx.sess(), attr.span) {
+                None
+            } else {
+                Some((attr, None))
+            }
+        }),
+        true,
+    );
     let mut doc = fragments.iter().fold(String::new(), |mut acc, fragment| {
         add_doc_fragment(&mut acc, fragment);
         acc
@@ -602,6 +611,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
     let mut text_to_check: Vec<(CowStr<'_>, Range<usize>, isize)> = Vec::new();
     let mut paragraph_range = 0..0;
     let mut code_level = 0;
+    let mut blockquote_level = 0;
 
     for (event, range) in events {
         match event {
@@ -610,8 +620,14 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
                     code_level += 1;
                 } else if tag.starts_with("</code") {
                     code_level -= 1;
+                } else if tag.starts_with("<blockquote") || tag.starts_with("<q") {
+                    blockquote_level += 1;
+                } else if tag.starts_with("</blockquote") || tag.starts_with("</q") {
+                    blockquote_level -= 1;
                 }
             },
+            Start(BlockQuote) => blockquote_level += 1,
+            End(BlockQuote) => blockquote_level -= 1,
             Start(CodeBlock(ref kind)) => {
                 in_code = true;
                 if let CodeBlockKind::Fenced(lang) = kind {
@@ -663,7 +679,7 @@ fn check_doc<'a, Events: Iterator<Item = (pulldown_cmark::Event<'a>, Range<usize
                 } else {
                     for (text, range, assoc_code_level) in text_to_check {
                         if let Some(span) = fragments.span(cx, range) {
-                            markdown::check(cx, valid_idents, &text, span, assoc_code_level);
+                            markdown::check(cx, valid_idents, &text, span, assoc_code_level, blockquote_level);
                         }
                     }
                 }
diff --git a/src/tools/clippy/clippy_lints/src/else_if_without_else.rs b/src/tools/clippy/clippy_lints/src/else_if_without_else.rs
index 47780cab9ed..a6ca7fe9e0b 100644
--- a/src/tools/clippy/clippy_lints/src/else_if_without_else.rs
+++ b/src/tools/clippy/clippy_lints/src/else_if_without_else.rs
@@ -49,24 +49,22 @@ declare_clippy_lint! {
 declare_lint_pass!(ElseIfWithoutElse => [ELSE_IF_WITHOUT_ELSE]);
 
 impl EarlyLintPass for ElseIfWithoutElse {
-    fn check_expr(&mut self, cx: &EarlyContext<'_>, mut item: &Expr) {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, item: &Expr) {
         if in_external_macro(cx.sess(), item.span) {
             return;
         }
 
-        while let ExprKind::If(_, _, Some(ref els)) = item.kind {
-            if let ExprKind::If(_, _, None) = els.kind {
-                span_lint_and_help(
-                    cx,
-                    ELSE_IF_WITHOUT_ELSE,
-                    els.span,
-                    "`if` expression with an `else if`, but without a final `else`",
-                    None,
-                    "add an `else` block here",
-                );
-            }
-
-            item = els;
+        if let ExprKind::If(_, _, Some(ref els)) = item.kind
+            && let ExprKind::If(_, _, None) = els.kind
+        {
+            span_lint_and_help(
+                cx,
+                ELSE_IF_WITHOUT_ELSE,
+                els.span,
+                "`if` expression with an `else if`, but without a final `else`",
+                None,
+                "add an `else` block here",
+            );
         }
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/entry.rs b/src/tools/clippy/clippy_lints/src/entry.rs
index ebda2ad8387..dafbf6c8846 100644
--- a/src/tools/clippy/clippy_lints/src/entry.rs
+++ b/src/tools/clippy/clippy_lints/src/entry.rs
@@ -358,7 +358,7 @@ struct InsertSearcher<'cx, 'tcx> {
     can_use_entry: bool,
     /// Whether this expression is the final expression in this code path. This may be a statement.
     in_tail_pos: bool,
-    // Is this expression a single insert. A slightly better suggestion can be made in this case.
+    /// Is this expression a single insert. A slightly better suggestion can be made in this case.
     is_single_insert: bool,
     /// If the visitor has seen the map being used.
     is_map_used: bool,
@@ -431,6 +431,9 @@ impl<'tcx> Visitor<'tcx> for InsertSearcher<'_, 'tcx> {
                     self.is_single_insert = false;
                     self.visit_expr(e);
                 }
+                if let Some(els) = &l.els {
+                    self.visit_block(els);
+                }
             },
             StmtKind::Item(_) => {
                 self.allow_insert_closure &= !self.in_tail_pos;
diff --git a/src/tools/clippy/clippy_lints/src/equatable_if_let.rs b/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
index 4e728d61b85..37442bf3e28 100644
--- a/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
+++ b/src/tools/clippy/clippy_lints/src/equatable_if_let.rs
@@ -55,7 +55,7 @@ fn unary_pattern(pat: &Pat<'_>) -> bool {
         | PatKind::Err(_) => false,
         PatKind::Struct(_, a, etc) => !etc && a.iter().all(|x| unary_pattern(x.pat)),
         PatKind::Tuple(a, etc) | PatKind::TupleStruct(_, a, etc) => etc.as_opt_usize().is_none() && array_rec(a),
-        PatKind::Ref(x, _) | PatKind::Box(x) => unary_pattern(x),
+        PatKind::Ref(x, _) | PatKind::Box(x) | PatKind::Deref(x) => unary_pattern(x),
         PatKind::Path(_) | PatKind::Lit(_) => true,
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/functions/mod.rs b/src/tools/clippy/clippy_lints/src/functions/mod.rs
index 96da2ec2a1a..9cc51fa8cd5 100644
--- a/src/tools/clippy/clippy_lints/src/functions/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/functions/mod.rs
@@ -250,7 +250,7 @@ declare_clippy_lint! {
     ///
     /// ### Why is this bad?
     /// A `Result` is at least as large as the `Err`-variant. While we
-    /// expect that variant to be seldomly used, the compiler needs to reserve
+    /// expect that variant to be seldom used, the compiler needs to reserve
     /// and move that much memory every single time.
     /// Furthermore, errors are often simply passed up the call-stack, making
     /// use of the `?`-operator and its type-conversion mechanics. If the
diff --git a/src/tools/clippy/clippy_lints/src/future_not_send.rs b/src/tools/clippy/clippy_lints/src/future_not_send.rs
index 9fb59a320d4..18f4e51ebd6 100644
--- a/src/tools/clippy/clippy_lints/src/future_not_send.rs
+++ b/src/tools/clippy/clippy_lints/src/future_not_send.rs
@@ -64,7 +64,7 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
         }
         let ret_ty = return_ty(cx, cx.tcx.local_def_id_to_hir_id(fn_def_id).expect_owner());
         if let ty::Alias(ty::Opaque, AliasTy { def_id, args, .. }) = *ret_ty.kind() {
-            let preds = cx.tcx.explicit_item_bounds(def_id);
+            let preds = cx.tcx.explicit_item_super_predicates(def_id);
             let mut is_future = false;
             for (p, _span) in preds.iter_instantiated_copied(cx.tcx, args) {
                 if let Some(trait_pred) = p.as_trait_clause() {
diff --git a/src/tools/clippy/clippy_lints/src/integer_division_remainder_used.rs b/src/tools/clippy/clippy_lints/src/integer_division_remainder_used.rs
new file mode 100644
index 00000000000..36dc45ca788
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/integer_division_remainder_used.rs
@@ -0,0 +1,50 @@
+use clippy_utils::diagnostics::span_lint;
+use rustc_ast::BinOpKind;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::{self};
+use rustc_session::declare_lint_pass;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for the usage of division (/) and remainder (%) operations
+    /// when performed on any integer types using the default Div and Rem trait implementations.
+    ///
+    /// ### Why is this bad?
+    /// In cryptographic contexts, division can result in timing sidechannel vulnerabilities,
+    /// and needs to be replaced with constant-time code instead (e.g. Barrett reduction).
+    ///
+    /// ### Example
+    /// ```no_run
+    /// let my_div = 10 / 2;
+    /// ```
+    /// Use instead:
+    /// ```no_run
+    /// let my_div = 10 >> 1;
+    /// ```
+    #[clippy::version = "1.78.0"]
+    pub INTEGER_DIVISION_REMAINDER_USED,
+    restriction,
+    "use of disallowed default division and remainder operations"
+}
+
+declare_lint_pass!(IntegerDivisionRemainderUsed => [INTEGER_DIVISION_REMAINDER_USED]);
+
+impl LateLintPass<'_> for IntegerDivisionRemainderUsed {
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
+        if let ExprKind::Binary(op, lhs, rhs) = &expr.kind
+            && let BinOpKind::Div | BinOpKind::Rem = op.node
+            && let lhs_ty = cx.typeck_results().expr_ty(lhs)
+            && let rhs_ty = cx.typeck_results().expr_ty(rhs)
+            && let ty::Int(_) | ty::Uint(_) = lhs_ty.peel_refs().kind()
+            && let ty::Int(_) | ty::Uint(_) = rhs_ty.peel_refs().kind()
+        {
+            span_lint(
+                cx,
+                INTEGER_DIVISION_REMAINDER_USED,
+                expr.span.source_callsite(),
+                &format!("use of {} has been disallowed in this context", op.node.as_str()),
+            );
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/let_if_seq.rs b/src/tools/clippy/clippy_lints/src/let_if_seq.rs
index f084d89ccc2..d4ddf76fb8a 100644
--- a/src/tools/clippy/clippy_lints/src/let_if_seq.rs
+++ b/src/tools/clippy/clippy_lints/src/let_if_seq.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::diagnostics::span_lint_hir_and_then;
 use clippy_utils::path_to_local_id;
 use clippy_utils::source::snippet;
 use clippy_utils::visitors::is_local_used;
@@ -122,9 +122,10 @@ impl<'tcx> LateLintPass<'tcx> for LetIfSeq {
                     value=snippet(cx, value.span, "<value>"),
                     default=snippet(cx, default.span, "<default>"),
                 );
-                span_lint_and_then(
+                span_lint_hir_and_then(
                     cx,
                     USELESS_LET_IF_SEQ,
+                    local.hir_id,
                     span,
                     "`if _ { .. } else { .. }` is an expression",
                     |diag| {
diff --git a/src/tools/clippy/clippy_lints/src/lib.rs b/src/tools/clippy/clippy_lints/src/lib.rs
index b930175c4d8..57fac351042 100644
--- a/src/tools/clippy/clippy_lints/src/lib.rs
+++ b/src/tools/clippy/clippy_lints/src/lib.rs
@@ -172,6 +172,7 @@ mod init_numbered_fields;
 mod inline_fn_without_body;
 mod instant_subtraction;
 mod int_plus_one;
+mod integer_division_remainder_used;
 mod invalid_upcast_comparisons;
 mod item_name_repetitions;
 mod items_after_statements;
@@ -211,6 +212,7 @@ mod manual_retain;
 mod manual_slice_size_calculation;
 mod manual_string_new;
 mod manual_strip;
+mod manual_unwrap_or_default;
 mod map_unit_fn;
 mod match_result_ok;
 mod matches;
@@ -373,6 +375,7 @@ mod visibility;
 mod wildcard_imports;
 mod write;
 mod zero_div_zero;
+mod zero_repeat_side_effects;
 mod zero_sized_map_values;
 // end lints modules, do not remove this comment, it’s used in `update_lints`
 
@@ -1119,7 +1122,10 @@ pub fn register_lints(store: &mut rustc_lint::LintStore, conf: &'static Conf) {
     store.register_late_pass(move |_| Box::new(incompatible_msrv::IncompatibleMsrv::new(msrv())));
     store.register_late_pass(|_| Box::new(to_string_trait_impl::ToStringTraitImpl));
     store.register_early_pass(|| Box::new(multiple_bound_locations::MultipleBoundLocations));
-    store.register_late_pass(|_| Box::new(assigning_clones::AssigningClones));
+    store.register_late_pass(move |_| Box::new(assigning_clones::AssigningClones::new(msrv())));
+    store.register_late_pass(|_| Box::new(zero_repeat_side_effects::ZeroRepeatSideEffects));
+    store.register_late_pass(|_| Box::new(manual_unwrap_or_default::ManualUnwrapOrDefault));
+    store.register_late_pass(|_| Box::new(integer_division_remainder_used::IntegerDivisionRemainderUsed));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 
diff --git a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
index 47dc3807e62..cf34c904dfe 100644
--- a/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/needless_range_loop.rs
@@ -273,7 +273,7 @@ impl<'a, 'tcx> VarVisitor<'a, 'tcx> {
                     }
                     return false; // no need to walk further *on the variable*
                 },
-                Res::Def(DefKind::Static{..} | DefKind::Const, ..) => {
+                Res::Def(DefKind::Static { .. } | DefKind::Const, ..) => {
                     if index_used_directly {
                         self.indexed_directly.insert(
                             seqvar.segments[0].ident.name,
diff --git a/src/tools/clippy/clippy_lints/src/loops/never_loop.rs b/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
index 6cc79440f39..8aae7be4593 100644
--- a/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/never_loop.rs
@@ -255,9 +255,7 @@ fn never_loop_expr<'tcx>(
             InlineAsmOperand::Const { .. } | InlineAsmOperand::SymFn { .. } | InlineAsmOperand::SymStatic { .. } => {
                 NeverLoopResult::Normal
             },
-            InlineAsmOperand::Label { block } => {
-                never_loop_block(cx, block, local_labels, main_loop_id)
-            }
+            InlineAsmOperand::Label { block } => never_loop_block(cx, block, local_labels, main_loop_id),
         })),
         ExprKind::OffsetOf(_, _)
         | ExprKind::Yield(_, _)
diff --git a/src/tools/clippy/clippy_lints/src/loops/unused_enumerate_index.rs b/src/tools/clippy/clippy_lints/src/loops/unused_enumerate_index.rs
index dd7fae79d9b..31f0f1cfeba 100644
--- a/src/tools/clippy/clippy_lints/src/loops/unused_enumerate_index.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/unused_enumerate_index.rs
@@ -1,62 +1,41 @@
 use super::UNUSED_ENUMERATE_INDEX;
 use clippy_utils::diagnostics::{multispan_sugg, span_lint_and_then};
 use clippy_utils::source::snippet;
-use clippy_utils::{pat_is_wild, sugg};
+use clippy_utils::{match_def_path, pat_is_wild, sugg};
 use rustc_hir::def::DefKind;
 use rustc_hir::{Expr, ExprKind, Pat, PatKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 
 /// Checks for the `UNUSED_ENUMERATE_INDEX` lint.
-pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, arg: &'tcx Expr<'_>, body: &'tcx Expr<'_>) {
-    let PatKind::Tuple([index, elem], _) = pat.kind else {
-        return;
-    };
-
-    let ExprKind::MethodCall(_method, self_arg, [], _) = arg.kind else {
-        return;
-    };
-
-    let ty = cx.typeck_results().expr_ty(arg);
-
-    if !pat_is_wild(cx, &index.kind, body) {
-        return;
-    }
-
-    let name = match *ty.kind() {
-        ty::Adt(base, _substs) => cx.tcx.def_path_str(base.did()),
-        _ => return,
-    };
-
-    if name != "std::iter::Enumerate" && name != "core::iter::Enumerate" {
-        return;
+///
+/// The lint is also partially implemented in `clippy_lints/src/methods/unused_enumerate_index.rs`.
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'tcx>, arg: &Expr<'_>, body: &'tcx Expr<'tcx>) {
+    if let PatKind::Tuple([index, elem], _) = pat.kind
+        && let ExprKind::MethodCall(_method, self_arg, [], _) = arg.kind
+        && let ty = cx.typeck_results().expr_ty(arg)
+        && pat_is_wild(cx, &index.kind, body)
+        && let ty::Adt(base, _) = *ty.kind()
+        && match_def_path(cx, base.did(), &clippy_utils::paths::CORE_ITER_ENUMERATE_STRUCT)
+        && let Some((DefKind::AssocFn, call_id)) = cx.typeck_results().type_dependent_def(arg.hir_id)
+        && match_def_path(cx, call_id, &clippy_utils::paths::CORE_ITER_ENUMERATE_METHOD)
+    {
+        span_lint_and_then(
+            cx,
+            UNUSED_ENUMERATE_INDEX,
+            arg.span,
+            "you seem to use `.enumerate()` and immediately discard the index",
+            |diag| {
+                let base_iter = sugg::Sugg::hir(cx, self_arg, "base iter");
+                multispan_sugg(
+                    diag,
+                    "remove the `.enumerate()` call",
+                    vec![
+                        (pat.span, snippet(cx, elem.span, "..").into_owned()),
+                        (arg.span, base_iter.to_string()),
+                    ],
+                );
+            },
+        );
     }
-
-    let Some((DefKind::AssocFn, call_id)) = cx.typeck_results().type_dependent_def(arg.hir_id) else {
-        return;
-    };
-
-    let call_name = cx.tcx.def_path_str(call_id);
-
-    if call_name != "std::iter::Iterator::enumerate" && call_name != "core::iter::Iterator::enumerate" {
-        return;
-    }
-
-    span_lint_and_then(
-        cx,
-        UNUSED_ENUMERATE_INDEX,
-        arg.span,
-        "you seem to use `.enumerate()` and immediately discard the index",
-        |diag| {
-            let base_iter = sugg::Sugg::hir(cx, self_arg, "base iter");
-            multispan_sugg(
-                diag,
-                "remove the `.enumerate()` call",
-                vec![
-                    (pat.span, snippet(cx, elem.span, "..").into_owned()),
-                    (arg.span, base_iter.to_string()),
-                ],
-            );
-        },
-    );
 }
diff --git a/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs b/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs
index 3511d24e813..3dff826cb85 100644
--- a/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs
@@ -101,7 +101,7 @@ impl<'a, 'tcx> VarCollectorVisitor<'a, 'tcx> {
                 Res::Local(hir_id) => {
                     self.ids.insert(hir_id);
                 },
-                Res::Def(DefKind::Static{..}, def_id) => {
+                Res::Def(DefKind::Static { .. }, def_id) => {
                     let mutable = self.cx.tcx.is_mutable_static(def_id);
                     self.def_ids.insert(def_id, mutable);
                 },
diff --git a/src/tools/clippy/clippy_lints/src/manual_retain.rs b/src/tools/clippy/clippy_lints/src/manual_retain.rs
index 6f15fca089e..3ddb06a1e08 100644
--- a/src/tools/clippy/clippy_lints/src/manual_retain.rs
+++ b/src/tools/clippy/clippy_lints/src/manual_retain.rs
@@ -2,7 +2,7 @@ use clippy_config::msrvs::{self, Msrv};
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet;
 use clippy_utils::ty::{is_type_diagnostic_item, is_type_lang_item};
-use clippy_utils::{get_parent_expr, match_def_path, paths, SpanlessEq};
+use clippy_utils::{match_def_path, paths, SpanlessEq};
 use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_hir::def_id::DefId;
@@ -69,17 +69,16 @@ impl_lint_pass!(ManualRetain => [MANUAL_RETAIN]);
 
 impl<'tcx> LateLintPass<'tcx> for ManualRetain {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if let Some(parent_expr) = get_parent_expr(cx, expr)
-            && let Assign(left_expr, collect_expr, _) = &parent_expr.kind
+        if let Assign(left_expr, collect_expr, _) = &expr.kind
             && let hir::ExprKind::MethodCall(seg, ..) = &collect_expr.kind
             && seg.args.is_none()
             && let hir::ExprKind::MethodCall(_, target_expr, [], _) = &collect_expr.kind
             && let Some(collect_def_id) = cx.typeck_results().type_dependent_def_id(collect_expr.hir_id)
             && cx.tcx.is_diagnostic_item(sym::iterator_collect_fn, collect_def_id)
         {
-            check_into_iter(cx, left_expr, target_expr, parent_expr.span, &self.msrv);
-            check_iter(cx, left_expr, target_expr, parent_expr.span, &self.msrv);
-            check_to_owned(cx, left_expr, target_expr, parent_expr.span, &self.msrv);
+            check_into_iter(cx, left_expr, target_expr, expr.span, &self.msrv);
+            check_iter(cx, left_expr, target_expr, expr.span, &self.msrv);
+            check_to_owned(cx, left_expr, target_expr, expr.span, &self.msrv);
         }
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/manual_unwrap_or_default.rs b/src/tools/clippy/clippy_lints/src/manual_unwrap_or_default.rs
new file mode 100644
index 00000000000..ddaf97c463a
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/manual_unwrap_or_default.rs
@@ -0,0 +1,181 @@
+use rustc_errors::Applicability;
+use rustc_hir::def::Res;
+use rustc_hir::{Arm, Expr, ExprKind, HirId, LangItem, MatchSource, Pat, PatKind, QPath};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::declare_lint_pass;
+use rustc_span::sym;
+
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::is_default_equivalent;
+use clippy_utils::source::snippet_opt;
+use clippy_utils::ty::implements_trait;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks if a `match` or `if let` expression can be simplified using
+    /// `.unwrap_or_default()`.
+    ///
+    /// ### Why is this bad?
+    /// It can be done in one call with `.unwrap_or_default()`.
+    ///
+    /// ### Example
+    /// ```no_run
+    /// let x: Option<String> = Some(String::new());
+    /// let y: String = match x {
+    ///     Some(v) => v,
+    ///     None => String::new(),
+    /// };
+    ///
+    /// let x: Option<Vec<String>> = Some(Vec::new());
+    /// let y: Vec<String> = if let Some(v) = x {
+    ///     v
+    /// } else {
+    ///     Vec::new()
+    /// };
+    /// ```
+    /// Use instead:
+    /// ```no_run
+    /// let x: Option<String> = Some(String::new());
+    /// let y: String = x.unwrap_or_default();
+    ///
+    /// let x: Option<Vec<String>> = Some(Vec::new());
+    /// let y: Vec<String> = x.unwrap_or_default();
+    /// ```
+    #[clippy::version = "1.78.0"]
+    pub MANUAL_UNWRAP_OR_DEFAULT,
+    suspicious,
+    "check if a `match` or `if let` can be simplified with `unwrap_or_default`"
+}
+
+declare_lint_pass!(ManualUnwrapOrDefault => [MANUAL_UNWRAP_OR_DEFAULT]);
+
+fn get_some<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'tcx>) -> Option<HirId> {
+    if let PatKind::TupleStruct(QPath::Resolved(_, path), &[pat], _) = pat.kind
+        && let Some(def_id) = path.res.opt_def_id()
+        // Since it comes from a pattern binding, we need to get the parent to actually match
+        // against it.
+        && let Some(def_id) = cx.tcx.opt_parent(def_id)
+        && cx.tcx.lang_items().get(LangItem::OptionSome) == Some(def_id)
+    {
+        let mut bindings = Vec::new();
+        pat.each_binding(|_, id, _, _| bindings.push(id));
+        if let &[id] = bindings.as_slice() {
+            Some(id)
+        } else {
+            None
+        }
+    } else {
+        None
+    }
+}
+
+fn get_none<'tcx>(cx: &LateContext<'tcx>, arm: &Arm<'tcx>) -> Option<&'tcx Expr<'tcx>> {
+    if let PatKind::Path(QPath::Resolved(_, path)) = arm.pat.kind
+        && let Some(def_id) = path.res.opt_def_id()
+        // Since it comes from a pattern binding, we need to get the parent to actually match
+        // against it.
+        && let Some(def_id) = cx.tcx.opt_parent(def_id)
+        && cx.tcx.lang_items().get(LangItem::OptionNone) == Some(def_id)
+    {
+        Some(arm.body)
+    } else if let PatKind::Wild = arm.pat.kind {
+        // We consider that the `Some` check will filter it out if it's not right.
+        Some(arm.body)
+    } else {
+        None
+    }
+}
+
+fn get_some_and_none_bodies<'tcx>(
+    cx: &LateContext<'tcx>,
+    arm1: &'tcx Arm<'tcx>,
+    arm2: &'tcx Arm<'tcx>,
+) -> Option<((&'tcx Expr<'tcx>, HirId), &'tcx Expr<'tcx>)> {
+    if let Some(binding_id) = get_some(cx, arm1.pat)
+        && let Some(body_none) = get_none(cx, arm2)
+    {
+        Some(((arm1.body, binding_id), body_none))
+    } else if let Some(binding_id) = get_some(cx, arm2.pat)
+        && let Some(body_none) = get_none(cx, arm1)
+    {
+        Some(((arm2.body, binding_id), body_none))
+    } else {
+        None
+    }
+}
+
+fn handle_match<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
+    let ExprKind::Match(match_expr, [arm1, arm2], MatchSource::Normal | MatchSource::ForLoopDesugar) = expr.kind else {
+        return false;
+    };
+    // We don't want conditions on the arms to simplify things.
+    if arm1.guard.is_none()
+        && arm2.guard.is_none()
+        // We check that the returned type implements the `Default` trait.
+        && let match_ty = cx.typeck_results().expr_ty(expr)
+        && let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default)
+        && implements_trait(cx, match_ty, default_trait_id, &[])
+        // We now get the bodies for both the `Some` and `None` arms.
+        && let Some(((body_some, binding_id), body_none)) = get_some_and_none_bodies(cx, arm1, arm2)
+        // We check that the `Some(x) => x` doesn't do anything apart "returning" the value in `Some`.
+        && let ExprKind::Path(QPath::Resolved(_, path)) = body_some.peel_blocks().kind
+        && let Res::Local(local_id) = path.res
+        && local_id == binding_id
+        // We now check the `None` arm is calling a method equivalent to `Default::default`.
+        && let body_none = body_none.peel_blocks()
+        && is_default_equivalent(cx, body_none)
+        && let Some(match_expr_snippet) = snippet_opt(cx, match_expr.span)
+    {
+        span_lint_and_sugg(
+            cx,
+            MANUAL_UNWRAP_OR_DEFAULT,
+            expr.span,
+            "match can be simplified with `.unwrap_or_default()`",
+            "replace it with",
+            format!("{match_expr_snippet}.unwrap_or_default()"),
+            Applicability::MachineApplicable,
+        );
+    }
+    true
+}
+
+fn handle_if_let<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
+    if let ExprKind::If(cond, if_block, Some(else_expr)) = expr.kind
+        && let ExprKind::Let(let_) = cond.kind
+        && let ExprKind::Block(_, _) = else_expr.kind
+        // We check that the returned type implements the `Default` trait.
+        && let match_ty = cx.typeck_results().expr_ty(expr)
+        && let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default)
+        && implements_trait(cx, match_ty, default_trait_id, &[])
+        && let Some(binding_id) = get_some(cx, let_.pat)
+        // We check that the `Some(x) => x` doesn't do anything apart "returning" the value in `Some`.
+        && let ExprKind::Path(QPath::Resolved(_, path)) = if_block.peel_blocks().kind
+        && let Res::Local(local_id) = path.res
+        && local_id == binding_id
+        // We now check the `None` arm is calling a method equivalent to `Default::default`.
+        && let body_else = else_expr.peel_blocks()
+        && is_default_equivalent(cx, body_else)
+        && let Some(if_let_expr_snippet) = snippet_opt(cx, let_.init.span)
+    {
+        span_lint_and_sugg(
+            cx,
+            MANUAL_UNWRAP_OR_DEFAULT,
+            expr.span,
+            "if let can be simplified with `.unwrap_or_default()`",
+            "replace it with",
+            format!("{if_let_expr_snippet}.unwrap_or_default()"),
+            Applicability::MachineApplicable,
+        );
+    }
+}
+
+impl<'tcx> LateLintPass<'tcx> for ManualUnwrapOrDefault {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
+        if expr.span.from_expansion() {
+            return;
+        }
+        if !handle_match(cx, expr) {
+            handle_if_let(cx, expr);
+        }
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs b/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs
index c7c453b7f6e..cd61e733694 100644
--- a/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/match_same_arms.rs
@@ -243,7 +243,7 @@ impl<'a> NormalizedPat<'a> {
     fn from_pat(cx: &LateContext<'_>, arena: &'a DroplessArena, pat: &'a Pat<'_>) -> Self {
         match pat.kind {
             PatKind::Wild | PatKind::Binding(.., None) => Self::Wild,
-            PatKind::Binding(.., Some(pat)) | PatKind::Box(pat) | PatKind::Ref(pat, _) => {
+            PatKind::Binding(.., Some(pat)) | PatKind::Box(pat) | PatKind::Deref(pat) | PatKind::Ref(pat, _) => {
                 Self::from_pat(cx, arena, pat)
             },
             PatKind::Never => Self::Never,
diff --git a/src/tools/clippy/clippy_lints/src/matches/single_match.rs b/src/tools/clippy/clippy_lints/src/matches/single_match.rs
index 86c414dafcc..a0db8e2db1f 100644
--- a/src/tools/clippy/clippy_lints/src/matches/single_match.rs
+++ b/src/tools/clippy/clippy_lints/src/matches/single_match.rs
@@ -55,23 +55,15 @@ pub(crate) fn check(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr:
         };
 
         let ty = cx.typeck_results().expr_ty(ex);
-        if *ty.kind() != ty::Bool || is_lint_allowed(cx, MATCH_BOOL, ex.hir_id) {
-            check_single_pattern(cx, ex, arms, expr, els);
-            check_opt_like(cx, ex, arms, expr, ty, els);
+        if (*ty.kind() != ty::Bool || is_lint_allowed(cx, MATCH_BOOL, ex.hir_id)) &&
+            (check_single_pattern(arms) || check_opt_like(cx, arms, ty)) {
+            report_single_pattern(cx, ex, arms, expr, els);
         }
     }
 }
 
-fn check_single_pattern(
-    cx: &LateContext<'_>,
-    ex: &Expr<'_>,
-    arms: &[Arm<'_>],
-    expr: &Expr<'_>,
-    els: Option<&Expr<'_>>,
-) {
-    if is_wild(arms[1].pat) {
-        report_single_pattern(cx, ex, arms, expr, els);
-    }
+fn check_single_pattern(arms: &[Arm<'_>]) -> bool {
+    is_wild(arms[1].pat)
 }
 
 fn report_single_pattern(
@@ -140,19 +132,10 @@ fn report_single_pattern(
     span_lint_and_sugg(cx, lint, expr.span, msg, "try", sugg, app);
 }
 
-fn check_opt_like<'a>(
-    cx: &LateContext<'a>,
-    ex: &Expr<'_>,
-    arms: &[Arm<'_>],
-    expr: &Expr<'_>,
-    ty: Ty<'a>,
-    els: Option<&Expr<'_>>,
-) {
+fn check_opt_like<'a>(cx: &LateContext<'a>, arms: &[Arm<'_>], ty: Ty<'a>) -> bool {
     // We don't want to lint if the second arm contains an enum which could
     // have more variants in the future.
-    if form_exhaustive_matches(cx, ty, arms[0].pat, arms[1].pat) {
-        report_single_pattern(cx, ex, arms, expr, els);
-    }
+    form_exhaustive_matches(cx, ty, arms[0].pat, arms[1].pat)
 }
 
 /// Returns `true` if all of the types in the pattern are enums which we know
diff --git a/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs b/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs
index e2c2997594a..4d8fb217f7f 100644
--- a/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/expect_fun_call.rs
@@ -91,7 +91,7 @@ pub(super) fn check<'tcx>(
             },
             hir::ExprKind::Path(ref p) => matches!(
                 cx.qpath_res(p, arg.hir_id),
-                hir::def::Res::Def(hir::def::DefKind::Const | hir::def::DefKind::Static{..}, _)
+                hir::def::Res::Def(hir::def::DefKind::Const | hir::def::DefKind::Static { .. }, _)
             ),
             _ => false,
         }
diff --git a/src/tools/clippy/clippy_lints/src/methods/is_empty.rs b/src/tools/clippy/clippy_lints/src/methods/is_empty.rs
new file mode 100644
index 00000000000..7fe66062251
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/is_empty.rs
@@ -0,0 +1,49 @@
+use clippy_utils::consts::constant_is_empty;
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::{find_binding_init, path_to_local};
+use rustc_hir::{Expr, HirId};
+use rustc_lint::{LateContext, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_span::sym;
+
+use super::CONST_IS_EMPTY;
+
+/// Expression whose initialization depend on a constant conditioned by a `#[cfg(…)]` directive will
+/// not trigger the lint.
+pub(super) fn check(cx: &LateContext<'_>, expr: &'_ Expr<'_>, receiver: &Expr<'_>) {
+    if in_external_macro(cx.sess(), expr.span) || !receiver.span.eq_ctxt(expr.span) {
+        return;
+    }
+    let init_expr = expr_or_init(cx, receiver);
+    if !receiver.span.eq_ctxt(init_expr.span) {
+        return;
+    }
+    if let Some(init_is_empty) = constant_is_empty(cx, init_expr) {
+        span_lint(
+            cx,
+            CONST_IS_EMPTY,
+            expr.span,
+            &format!("this expression always evaluates to {init_is_empty:?}"),
+        );
+    }
+}
+
+fn is_under_cfg(cx: &LateContext<'_>, id: HirId) -> bool {
+    cx.tcx
+        .hir()
+        .parent_id_iter(id)
+        .any(|id| cx.tcx.hir().attrs(id).iter().any(|attr| attr.has_name(sym::cfg)))
+}
+
+/// Similar to [`clippy_utils::expr_or_init`], but does not go up the chain if the initialization
+/// value depends on a `#[cfg(…)]` directive.
+fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
+    while let Some(init) = path_to_local(expr)
+        .and_then(|id| find_binding_init(cx, id))
+        .filter(|init| cx.typeck_results().expr_adjustments(init).is_empty())
+        .filter(|init| !is_under_cfg(cx, init.hir_id))
+    {
+        expr = init;
+    }
+    expr
+}
diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_nth.rs b/src/tools/clippy/clippy_lints/src/methods/iter_nth.rs
index 12104310405..5b0b70b4b96 100644
--- a/src/tools/clippy/clippy_lints/src/methods/iter_nth.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_nth.rs
@@ -1,10 +1,10 @@
-use super::utils::derefs_to_slice;
-use crate::methods::iter_nth_zero;
-use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::ty::get_type_diagnostic_name;
+use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::LateContext;
 use rustc_span::symbol::sym;
+use rustc_span::Span;
 
 use super::ITER_NTH;
 
@@ -12,28 +12,33 @@ pub(super) fn check<'tcx>(
     cx: &LateContext<'tcx>,
     expr: &hir::Expr<'_>,
     iter_recv: &'tcx hir::Expr<'tcx>,
-    nth_recv: &hir::Expr<'_>,
-    nth_arg: &hir::Expr<'_>,
-    is_mut: bool,
-) {
-    let mut_str = if is_mut { "_mut" } else { "" };
-    let caller_type = if derefs_to_slice(cx, iter_recv, cx.typeck_results().expr_ty(iter_recv)).is_some() {
-        "slice"
-    } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(iter_recv), sym::Vec) {
-        "`Vec`"
-    } else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(iter_recv), sym::VecDeque) {
-        "`VecDeque`"
-    } else {
-        iter_nth_zero::check(cx, expr, nth_recv, nth_arg);
-        return; // caller is not a type that we want to lint
+    iter_method: &str,
+    iter_span: Span,
+    nth_span: Span,
+) -> bool {
+    let caller_type = match get_type_diagnostic_name(cx, cx.typeck_results().expr_ty(iter_recv).peel_refs()) {
+        Some(sym::Vec) => "`Vec`",
+        Some(sym::VecDeque) => "`VecDeque`",
+        _ if cx.typeck_results().expr_ty_adjusted(iter_recv).peel_refs().is_slice() => "slice",
+        // caller is not a type that we want to lint
+        _ => return false,
     };
 
-    span_lint_and_help(
+    span_lint_and_then(
         cx,
         ITER_NTH,
         expr.span,
-        &format!("called `.iter{mut_str}().nth()` on a {caller_type}"),
-        None,
-        &format!("calling `.get{mut_str}()` is both faster and more readable"),
+        &format!("called `.{iter_method}().nth()` on a {caller_type}"),
+        |diag| {
+            let get_method = if iter_method == "iter_mut" { "get_mut" } else { "get" };
+            diag.span_suggestion_verbose(
+                iter_span.to(nth_span),
+                format!("`{get_method}` is equivalent but more concise"),
+                get_method,
+                Applicability::MachineApplicable,
+            );
+        },
     );
+
+    true
 }
diff --git a/src/tools/clippy/clippy_lints/src/methods/map_clone.rs b/src/tools/clippy/clippy_lints/src/methods/map_clone.rs
index 27e17b43b01..c3c7a3a0033 100644
--- a/src/tools/clippy/clippy_lints/src/methods/map_clone.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/map_clone.rs
@@ -86,8 +86,11 @@ pub(super) fn check(cx: &LateContext<'_>, e: &hir::Expr<'_>, recv: &hir::Expr<'_
                                     }
                                 }
                             },
-                            hir::ExprKind::Call(call, [_]) => {
-                                if let hir::ExprKind::Path(qpath) = call.kind {
+                            hir::ExprKind::Call(call, args) => {
+                                if let hir::ExprKind::Path(qpath) = call.kind
+                                    && let [arg] = args
+                                    && ident_eq(name, arg)
+                                {
                                     handle_path(cx, call, &qpath, e, recv);
                                 }
                             },
@@ -118,7 +121,9 @@ fn handle_path(
         if let ty::Adt(_, args) = cx.typeck_results().expr_ty(recv).kind()
             && let args = args.as_slice()
             && let Some(ty) = args.iter().find_map(|generic_arg| generic_arg.as_type())
-            && ty.is_ref()
+            && let ty::Ref(_, ty, Mutability::Not) = ty.kind()
+            && let ty::FnDef(_, lst) = cx.typeck_results().expr_ty(arg).kind()
+            && lst.iter().all(|l| l.as_type() == Some(*ty))
         {
             lint_path(cx, e.span, recv.span, is_copy(cx, ty.peel_refs()));
         }
diff --git a/src/tools/clippy/clippy_lints/src/methods/mod.rs b/src/tools/clippy/clippy_lints/src/methods/mod.rs
index 8a24ccea3a1..b6c474212cd 100644
--- a/src/tools/clippy/clippy_lints/src/methods/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/mod.rs
@@ -36,6 +36,7 @@ mod inefficient_to_string;
 mod inspect_for_each;
 mod into_iter_on_ref;
 mod is_digit_ascii_radix;
+mod is_empty;
 mod iter_cloned_collect;
 mod iter_count;
 mod iter_filter;
@@ -118,6 +119,7 @@ mod unnecessary_literal_unwrap;
 mod unnecessary_result_map_or_else;
 mod unnecessary_sort_by;
 mod unnecessary_to_owned;
+mod unused_enumerate_index;
 mod unwrap_expect_used;
 mod useless_asref;
 mod utils;
@@ -1235,12 +1237,11 @@ declare_clippy_lint! {
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for usage of `.iter().nth()` (and the related
-    /// `.iter_mut().nth()`) on standard library types with *O*(1) element access.
+    /// Checks for usage of `.iter().nth()`/`.iter_mut().nth()` on standard library types that have
+    /// equivalent `.get()`/`.get_mut()` methods.
     ///
     /// ### Why is this bad?
-    /// `.get()` and `.get_mut()` are more efficient and more
-    /// readable.
+    /// `.get()` and `.get_mut()` are equivalent but more concise.
     ///
     /// ### Example
     /// ```no_run
@@ -1256,7 +1257,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub ITER_NTH,
-    perf,
+    style,
     "using `.iter().nth()` on a standard library type with O(1) element access"
 }
 
@@ -2848,7 +2849,7 @@ declare_clippy_lint! {
     /// the file is created from scratch, or ensure `truncate` is
     /// called so that the truncation behaviour is explicit. `truncate(true)`
     /// will ensure the file is entirely overwritten with new data, whereas
-    /// `truncate(false)` will explicitely keep the default behavior.
+    /// `truncate(false)` will explicitly keep the default behavior.
     ///
     /// ### Example
     /// ```rust,no_run
@@ -2862,7 +2863,7 @@ declare_clippy_lint! {
     ///
     /// OpenOptions::new().create(true).truncate(true);
     /// ```
-    #[clippy::version = "1.75.0"]
+    #[clippy::version = "1.77.0"]
     pub SUSPICIOUS_OPEN_OPTIONS,
     suspicious,
     "suspicious combination of options for opening a file"
@@ -3182,8 +3183,8 @@ declare_clippy_lint! {
 declare_clippy_lint! {
     /// ### What it does
     ///
-    /// Checks an argument of `seek` method of `Seek` trait
-    /// and if it start seek from `SeekFrom::Current(0)`, suggests `stream_position` instead.
+    /// Checks if the `seek` method of the `Seek` trait is called with `SeekFrom::Current(0)`,
+    /// and if it is, suggests using `stream_position` instead.
     ///
     /// ### Why is this bad?
     ///
@@ -3590,7 +3591,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.73.0"]
     pub READONLY_WRITE_LOCK,
-    nursery,
+    perf,
     "acquiring a write lock when a read lock would work"
 }
 
@@ -3816,7 +3817,7 @@ declare_clippy_lint! {
     /// ```no_run
     /// let _ = std::iter::empty::<Result<i32, ()>>().flatten();
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub RESULT_FILTER_MAP,
     complexity,
     "filtering `Result` for `Ok` then force-unwrapping, which can be one type-safe operation"
@@ -3825,7 +3826,7 @@ declare_clippy_lint! {
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for usage of `.filter(Option::is_some)` that may be replaced with a `.flatten()` call.
-    /// This lint will require additional changes to the follow-up calls as it appects the type.
+    /// This lint will require additional changes to the follow-up calls as it affects the type.
     ///
     /// ### Why is this bad?
     /// This pattern is often followed by manual unwrapping of the `Option`. The simplification
@@ -3842,7 +3843,7 @@ declare_clippy_lint! {
     /// // example code which does not raise clippy warning
     /// vec![Some(1)].into_iter().flatten();
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub ITER_FILTER_IS_SOME,
     pedantic,
     "filtering an iterator over `Option`s for `Some` can be achieved with `flatten`"
@@ -3851,7 +3852,7 @@ declare_clippy_lint! {
 declare_clippy_lint! {
     /// ### What it does
     /// Checks for usage of `.filter(Result::is_ok)` that may be replaced with a `.flatten()` call.
-    /// This lint will require additional changes to the follow-up calls as it appects the type.
+    /// This lint will require additional changes to the follow-up calls as it affects the type.
     ///
     /// ### Why is this bad?
     /// This pattern is often followed by manual unwrapping of `Result`. The simplification
@@ -3868,7 +3869,7 @@ declare_clippy_lint! {
     /// // example code which does not raise clippy warning
     /// vec![Ok::<i32, String>(1)].into_iter().flatten();
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub ITER_FILTER_IS_OK,
     pedantic,
     "filtering an iterator over `Result`s for `Ok` can be achieved with `flatten`"
@@ -3895,7 +3896,7 @@ declare_clippy_lint! {
     /// option.is_some_and(|a| a > 10);
     /// result.is_ok_and(|a| a > 10);
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub MANUAL_IS_VARIANT_AND,
     pedantic,
     "using `.map(f).unwrap_or_default()`, which is more succinctly expressed as `is_some_and(f)` or `is_ok_and(f)`"
@@ -3925,7 +3926,7 @@ declare_clippy_lint! {
     /// `"\r\n"`), for example during the parsing of a specific file format in which precisely one newline type is
     /// valid.
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub STR_SPLIT_AT_NEWLINE,
     pedantic,
     "splitting a trimmed string at hard-coded newlines"
@@ -4044,6 +4045,31 @@ declare_clippy_lint! {
     "calling `.get().is_some()` or `.get().is_none()` instead of `.contains()` or `.contains_key()`"
 }
 
+declare_clippy_lint! {
+    /// ### What it does
+    /// It identifies calls to `.is_empty()` on constant values.
+    ///
+    /// ### Why is this bad?
+    /// String literals and constant values are known at compile time. Checking if they
+    /// are empty will always return the same value. This might not be the intention of
+    /// the expression.
+    ///
+    /// ### Example
+    /// ```no_run
+    /// let value = "";
+    /// if value.is_empty() {
+    ///     println!("the string is empty");
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```no_run
+    /// println!("the string is empty");
+    /// ```
+    #[clippy::version = "1.78.0"]
+    pub CONST_IS_EMPTY,
+    suspicious,
+    "is_empty() called on strings known at compile time"
+}
 pub struct Methods {
     avoid_breaking_exported_api: bool,
     msrv: Msrv,
@@ -4092,6 +4118,7 @@ impl_lint_pass!(Methods => [
     CLONE_ON_COPY,
     CLONE_ON_REF_PTR,
     COLLAPSIBLE_STR_REPLACE,
+    CONST_IS_EMPTY,
     ITER_OVEREAGER_CLONED,
     CLONED_INSTEAD_OF_COPIED,
     FLAT_MAP_OPTION,
@@ -4403,6 +4430,7 @@ impl Methods {
                     zst_offset::check(cx, expr, recv);
                 },
                 ("all", [arg]) => {
+                    unused_enumerate_index::check(cx, expr, recv, arg);
                     if let Some(("cloned", recv2, [], _, _)) = method_call(recv) {
                         iter_overeager_cloned::check(
                             cx,
@@ -4421,23 +4449,26 @@ impl Methods {
                         unnecessary_lazy_eval::check(cx, expr, recv, arg, "and");
                     }
                 },
-                ("any", [arg]) => match method_call(recv) {
-                    Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(
-                        cx,
-                        expr,
-                        recv,
-                        recv2,
-                        iter_overeager_cloned::Op::NeedlessMove(arg),
-                        false,
-                    ),
-                    Some(("chars", recv, _, _, _))
-                        if let ExprKind::Closure(arg) = arg.kind
-                            && let body = cx.tcx.hir().body(arg.body)
-                            && let [param] = body.params =>
-                    {
-                        string_lit_chars_any::check(cx, expr, recv, param, peel_blocks(body.value), &self.msrv);
-                    },
-                    _ => {},
+                ("any", [arg]) => {
+                    unused_enumerate_index::check(cx, expr, recv, arg);
+                    match method_call(recv) {
+                        Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(
+                            cx,
+                            expr,
+                            recv,
+                            recv2,
+                            iter_overeager_cloned::Op::NeedlessMove(arg),
+                            false,
+                        ),
+                        Some(("chars", recv, _, _, _))
+                            if let ExprKind::Closure(arg) = arg.kind
+                                && let body = cx.tcx.hir().body(arg.body)
+                                && let [param] = body.params =>
+                        {
+                            string_lit_chars_any::check(cx, expr, recv, param, peel_blocks(body.value), &self.msrv);
+                        },
+                        _ => {},
+                    }
                 },
                 ("arg", [arg]) => {
                     suspicious_command_arg_space::check(cx, recv, arg, span);
@@ -4445,7 +4476,7 @@ impl Methods {
                 ("as_deref" | "as_deref_mut", []) => {
                     needless_option_as_deref::check(cx, expr, recv, name);
                 },
-                ("as_bytes" | "is_empty", []) => {
+                ("as_bytes", []) => {
                     if let Some(("as_str", recv, [], as_str_span, _)) = method_call(recv) {
                         redundant_as_str::check(cx, expr, recv, as_str_span, span);
                     }
@@ -4570,14 +4601,17 @@ impl Methods {
                     }
                 },
                 ("filter_map", [arg]) => {
+                    unused_enumerate_index::check(cx, expr, recv, arg);
                     unnecessary_filter_map::check(cx, expr, arg, name);
                     filter_map_bool_then::check(cx, expr, arg, call_span);
                     filter_map_identity::check(cx, expr, arg, span);
                 },
                 ("find_map", [arg]) => {
+                    unused_enumerate_index::check(cx, expr, recv, arg);
                     unnecessary_filter_map::check(cx, expr, arg, name);
                 },
                 ("flat_map", [arg]) => {
+                    unused_enumerate_index::check(cx, expr, recv, arg);
                     flat_map_identity::check(cx, expr, arg, span);
                     flat_map_option::check(cx, expr, arg, span);
                 },
@@ -4599,17 +4633,20 @@ impl Methods {
                     manual_try_fold::check(cx, expr, init, acc, call_span, &self.msrv);
                     unnecessary_fold::check(cx, expr, init, acc, span);
                 },
-                ("for_each", [arg]) => match method_call(recv) {
-                    Some(("inspect", _, [_], span2, _)) => inspect_for_each::check(cx, expr, span2),
-                    Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(
-                        cx,
-                        expr,
-                        recv,
-                        recv2,
-                        iter_overeager_cloned::Op::NeedlessMove(arg),
-                        false,
-                    ),
-                    _ => {},
+                ("for_each", [arg]) => {
+                    unused_enumerate_index::check(cx, expr, recv, arg);
+                    match method_call(recv) {
+                        Some(("inspect", _, [_], span2, _)) => inspect_for_each::check(cx, expr, span2),
+                        Some(("cloned", recv2, [], _, _)) => iter_overeager_cloned::check(
+                            cx,
+                            expr,
+                            recv,
+                            recv2,
+                            iter_overeager_cloned::Op::NeedlessMove(arg),
+                            false,
+                        ),
+                        _ => {},
+                    }
                 },
                 ("get", [arg]) => {
                     get_first::check(cx, expr, recv, arg);
@@ -4619,6 +4656,12 @@ impl Methods {
                 ("hash", [arg]) => {
                     unit_hash::check(cx, expr, recv, arg);
                 },
+                ("is_empty", []) => {
+                    if let Some(("as_str", recv, [], as_str_span, _)) = method_call(recv) {
+                        redundant_as_str::check(cx, expr, recv, as_str_span, span);
+                    }
+                    is_empty::check(cx, expr, recv);
+                },
                 ("is_file", []) => filetype_is_file::check(cx, expr, recv),
                 ("is_digit", [radix]) => is_digit_ascii_radix::check(cx, expr, recv, radix, &self.msrv),
                 ("is_none", []) => check_is_some_is_none(cx, expr, recv, call_span, false),
@@ -4650,6 +4693,7 @@ impl Methods {
                 },
                 (name @ ("map" | "map_err"), [m_arg]) => {
                     if name == "map" {
+                        unused_enumerate_index::check(cx, expr, recv, m_arg);
                         map_clone::check(cx, expr, recv, m_arg, &self.msrv);
                         match method_call(recv) {
                             Some((map_name @ ("iter" | "into_iter"), recv2, _, _, _)) => {
@@ -4723,8 +4767,11 @@ impl Methods {
                         iter_overeager_cloned::Op::LaterCloned,
                         false,
                     ),
-                    Some(("iter", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, false),
-                    Some(("iter_mut", recv2, [], _, _)) => iter_nth::check(cx, expr, recv2, recv, n_arg, true),
+                    Some((iter_method @ ("iter" | "iter_mut"), iter_recv, [], iter_span, _)) => {
+                        if !iter_nth::check(cx, expr, iter_recv, iter_method, iter_span, span) {
+                            iter_nth_zero::check(cx, expr, recv, n_arg);
+                        }
+                    },
                     _ => iter_nth_zero::check(cx, expr, recv, n_arg),
                 },
                 ("ok_or_else", [arg]) => unnecessary_lazy_eval::check(cx, expr, recv, arg, "ok_or"),
diff --git a/src/tools/clippy/clippy_lints/src/methods/no_effect_replace.rs b/src/tools/clippy/clippy_lints/src/methods/no_effect_replace.rs
index 81df32bdee2..a301a5f7d65 100644
--- a/src/tools/clippy/clippy_lints/src/methods/no_effect_replace.rs
+++ b/src/tools/clippy/clippy_lints/src/methods/no_effect_replace.rs
@@ -25,6 +25,7 @@ pub(super) fn check<'tcx>(
         && param1 == param2.as_str()
     {
         span_lint(cx, NO_EFFECT_REPLACE, expr.span, "replacing text with itself");
+        return;
     }
 
     if SpanlessEq::new(cx).eq_expr(arg1, arg2) {
diff --git a/src/tools/clippy/clippy_lints/src/methods/unused_enumerate_index.rs b/src/tools/clippy/clippy_lints/src/methods/unused_enumerate_index.rs
new file mode 100644
index 00000000000..e5cc898612e
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/unused_enumerate_index.rs
@@ -0,0 +1,135 @@
+use clippy_utils::diagnostics::{multispan_sugg_with_applicability, span_lint_hir_and_then};
+use clippy_utils::paths::{CORE_ITER_ENUMERATE_METHOD, CORE_ITER_ENUMERATE_STRUCT};
+use clippy_utils::source::{snippet, snippet_opt};
+use clippy_utils::{expr_or_init, is_trait_method, match_def_path, pat_is_wild};
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind, FnDecl, PatKind, TyKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::AdtDef;
+use rustc_span::{sym, Span};
+
+use crate::loops::UNUSED_ENUMERATE_INDEX;
+
+/// Check for the `UNUSED_ENUMERATE_INDEX` lint outside of loops.
+///
+/// The lint is declared in `clippy_lints/src/loops/mod.rs`. There, the following pattern is
+/// checked:
+/// ```ignore
+/// for (_, x) in some_iter.enumerate() {
+///     // Index is ignored
+/// }
+/// ```
+///
+/// This `check` function checks for chained method calls constructs where we can detect that the
+/// index is unused. Currently, this checks only for the following patterns:
+/// ```ignore
+/// some_iter.enumerate().map_function(|(_, x)| ..)
+/// let x = some_iter.enumerate();
+/// x.map_function(|(_, x)| ..)
+/// ```
+/// where `map_function` is one of `all`, `any`, `filter_map`, `find_map`, `flat_map`, `for_each` or
+/// `map`.
+///
+/// # Preconditions
+/// This function must be called not on the `enumerate` call expression itself, but on any of the
+/// map functions listed above. It will ensure that `recv` is a `std::iter::Enumerate` instance and
+/// that the method call is one of the `std::iter::Iterator` trait.
+///
+/// * `call_expr`: The map function call expression
+/// * `recv`: The receiver of the call
+/// * `closure_arg`: The argument to the map function call containing the closure/function to apply
+pub(super) fn check(cx: &LateContext<'_>, call_expr: &Expr<'_>, recv: &Expr<'_>, closure_arg: &Expr<'_>) {
+    let recv_ty = cx.typeck_results().expr_ty(recv);
+    if let Some(recv_ty_defid) = recv_ty.ty_adt_def().map(AdtDef::did)
+        // If we call a method on a `std::iter::Enumerate` instance
+        && match_def_path(cx, recv_ty_defid, &CORE_ITER_ENUMERATE_STRUCT)
+        // If we are calling a method of the `Iterator` trait
+        && is_trait_method(cx, call_expr, sym::Iterator)
+        // And the map argument is a closure
+        && let ExprKind::Closure(closure) = closure_arg.kind
+        && let closure_body = cx.tcx.hir().body(closure.body)
+        // And that closure has one argument ...
+        && let [closure_param] = closure_body.params
+        // .. which is a tuple of 2 elements
+        && let PatKind::Tuple([index, elem], ..) = closure_param.pat.kind
+        // And that the first element (the index) is either `_` or unused in the body
+        && pat_is_wild(cx, &index.kind, closure_body)
+        // Try to find the initializer for `recv`. This is needed in case `recv` is a local_binding. In the
+        // first example below, `expr_or_init` would return `recv`.
+        // ```
+        // iter.enumerate().map(|(_, x)| x)
+        // ^^^^^^^^^^^^^^^^ `recv`, a call to `std::iter::Iterator::enumerate`
+        //
+        // let binding = iter.enumerate();
+        //               ^^^^^^^^^^^^^^^^ `recv_init_expr`
+        // binding.map(|(_, x)| x)
+        // ^^^^^^^ `recv`, not a call to `std::iter::Iterator::enumerate`
+        // ```
+        && let recv_init_expr = expr_or_init(cx, recv)
+        // Make sure the initializer is a method call. It may be that the `Enumerate` comes from something
+        // that we cannot control.
+        // This would for instance happen with:
+        // ```
+        // external_lib::some_function_returning_enumerate().map(|(_, x)| x)
+        // ```
+        && let ExprKind::MethodCall(_, enumerate_recv, _, enumerate_span) = recv_init_expr.kind
+        && let Some(enumerate_defid) = cx.typeck_results().type_dependent_def_id(recv_init_expr.hir_id)
+        // Make sure the method call is `std::iter::Iterator::enumerate`.
+        && match_def_path(cx, enumerate_defid, &CORE_ITER_ENUMERATE_METHOD)
+    {
+        // Check if the tuple type was explicit. It may be the type system _needs_ the type of the element
+        // that would be explicited in the closure.
+        let new_closure_param = match find_elem_explicit_type_span(closure.fn_decl) {
+            // We have an explicit type. Get its snippet, that of the binding name, and do `binding: ty`.
+            // Fallback to `..` if we fail getting either snippet.
+            Some(ty_span) => snippet_opt(cx, elem.span)
+                .and_then(|binding_name| snippet_opt(cx, ty_span).map(|ty_name| format!("{binding_name}: {ty_name}")))
+                .unwrap_or_else(|| "..".to_string()),
+            // Otherwise, we have no explicit type. We can replace with the binding name of the element.
+            None => snippet(cx, elem.span, "..").into_owned(),
+        };
+
+        // Suggest removing the tuple from the closure and the preceding call to `enumerate`, whose span we
+        // can get from the `MethodCall`.
+        span_lint_hir_and_then(
+            cx,
+            UNUSED_ENUMERATE_INDEX,
+            recv_init_expr.hir_id,
+            enumerate_span,
+            "you seem to use `.enumerate()` and immediately discard the index",
+            |diag| {
+                multispan_sugg_with_applicability(
+                    diag,
+                    "remove the `.enumerate()` call",
+                    Applicability::MachineApplicable,
+                    vec![
+                        (closure_param.span, new_closure_param),
+                        (
+                            enumerate_span.with_lo(enumerate_recv.span.source_callsite().hi()),
+                            String::new(),
+                        ),
+                    ],
+                );
+            },
+        );
+    }
+}
+
+/// Find the span of the explicit type of the element.
+///
+/// # Returns
+/// If the tuple argument:
+/// * Has no explicit type, returns `None`
+/// * Has an explicit tuple type with an implicit element type (`(usize, _)`), returns `None`
+/// * Has an explicit tuple type with an explicit element type (`(_, i32)`), returns the span for
+///   the element type.
+fn find_elem_explicit_type_span(fn_decl: &FnDecl<'_>) -> Option<Span> {
+    if let [tuple_ty] = fn_decl.inputs
+        && let TyKind::Tup([_idx_ty, elem_ty]) = tuple_ty.kind
+        && !matches!(elem_ty.kind, TyKind::Err(..) | TyKind::Infer)
+    {
+        Some(elem_ty.span)
+    } else {
+        None
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/missing_doc.rs b/src/tools/clippy/clippy_lints/src/missing_doc.rs
index bf4af7946f4..6878fb3349d 100644
--- a/src/tools/clippy/clippy_lints/src/missing_doc.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_doc.rs
@@ -8,6 +8,7 @@
 use clippy_utils::attrs::is_doc_hidden;
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::is_from_proc_macro;
+use clippy_utils::source::snippet_opt;
 use rustc_ast::ast::{self, MetaItem, MetaItemKind};
 use rustc_hir as hir;
 use rustc_hir::def_id::LocalDefId;
@@ -32,6 +33,13 @@ declare_clippy_lint! {
     "detects missing documentation for private members"
 }
 
+macro_rules! note_prev_span_then_ret {
+    ($prev_span:expr, $span:expr) => {{
+        $prev_span = Some($span);
+        return;
+    }};
+}
+
 pub struct MissingDoc {
     /// Whether to **only** check for missing documentation in items visible within the current
     /// crate. For example, `pub(crate)` items.
@@ -39,6 +47,8 @@ pub struct MissingDoc {
     /// Stack of whether #[doc(hidden)] is set
     /// at each level which has lint attributes.
     doc_hidden_stack: Vec<bool>,
+    /// Used to keep tracking of the previous item, field or variants etc, to get the search span.
+    prev_span: Option<Span>,
 }
 
 impl Default for MissingDoc {
@@ -54,6 +64,7 @@ impl MissingDoc {
         Self {
             crate_items_only,
             doc_hidden_stack: vec![false],
+            prev_span: None,
         }
     }
 
@@ -108,7 +119,8 @@ impl MissingDoc {
 
         let has_doc = attrs
             .iter()
-            .any(|a| a.doc_str().is_some() || Self::has_include(a.meta()));
+            .any(|a| a.doc_str().is_some() || Self::has_include(a.meta()))
+            || matches!(self.search_span(sp), Some(span) if span_to_snippet_contains_docs(cx, span));
 
         if !has_doc {
             span_lint(
@@ -119,6 +131,32 @@ impl MissingDoc {
             );
         }
     }
+
+    /// Return a span to search for doc comments manually.
+    ///
+    /// # Example
+    /// ```ignore
+    /// fn foo() { ... }
+    /// ^^^^^^^^^^^^^^^^ prev_span
+    ///                ↑
+    /// |  search_span |
+    /// ↓
+    /// fn bar() { ... }
+    /// ^^^^^^^^^^^^^^^^ cur_span
+    /// ```
+    fn search_span(&self, cur_span: Span) -> Option<Span> {
+        let prev_span = self.prev_span?;
+        let start_pos = if prev_span.contains(cur_span) {
+            // In case when the prev_span is an entire struct, or enum,
+            // and the current span is a field, or variant, we need to search from
+            // the starting pos of the previous span.
+            prev_span.lo()
+        } else {
+            prev_span.hi()
+        };
+        let search_span = cur_span.with_lo(start_pos).with_hi(cur_span.lo());
+        Some(search_span)
+    }
 }
 
 impl_lint_pass!(MissingDoc => [MISSING_DOCS_IN_PRIVATE_ITEMS]);
@@ -138,6 +176,10 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
         self.check_missing_docs_attrs(cx, CRATE_DEF_ID, attrs, cx.tcx.def_span(CRATE_DEF_ID), "the", "crate");
     }
 
+    fn check_crate_post(&mut self, _: &LateContext<'tcx>) {
+        self.prev_span = None;
+    }
+
     fn check_item(&mut self, cx: &LateContext<'tcx>, it: &'tcx hir::Item<'_>) {
         match it.kind {
             hir::ItemKind::Fn(..) => {
@@ -145,7 +187,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
                 if it.ident.name == sym::main {
                     let at_root = cx.tcx.local_parent(it.owner_id.def_id) == CRATE_DEF_ID;
                     if at_root {
-                        return;
+                        note_prev_span_then_ret!(self.prev_span, it.span);
                     }
                 }
             },
@@ -164,7 +206,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
             | hir::ItemKind::ForeignMod { .. }
             | hir::ItemKind::GlobalAsm(..)
             | hir::ItemKind::Impl { .. }
-            | hir::ItemKind::Use(..) => return,
+            | hir::ItemKind::Use(..) => note_prev_span_then_ret!(self.prev_span, it.span),
         };
 
         let (article, desc) = cx.tcx.article_and_description(it.owner_id.to_def_id());
@@ -173,6 +215,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
         if !is_from_proc_macro(cx, it) {
             self.check_missing_docs_attrs(cx, it.owner_id.def_id, attrs, it.span, article, desc);
         }
+        self.prev_span = Some(it.span);
     }
 
     fn check_trait_item(&mut self, cx: &LateContext<'tcx>, trait_item: &'tcx hir::TraitItem<'_>) {
@@ -182,16 +225,17 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
         if !is_from_proc_macro(cx, trait_item) {
             self.check_missing_docs_attrs(cx, trait_item.owner_id.def_id, attrs, trait_item.span, article, desc);
         }
+        self.prev_span = Some(trait_item.span);
     }
 
     fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &'tcx hir::ImplItem<'_>) {
         // If the method is an impl for a trait, don't doc.
         if let Some(cid) = cx.tcx.associated_item(impl_item.owner_id).impl_container(cx.tcx) {
             if cx.tcx.impl_trait_ref(cid).is_some() {
-                return;
+                note_prev_span_then_ret!(self.prev_span, impl_item.span);
             }
         } else {
-            return;
+            note_prev_span_then_ret!(self.prev_span, impl_item.span);
         }
 
         let (article, desc) = cx.tcx.article_and_description(impl_item.owner_id.to_def_id());
@@ -199,6 +243,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
         if !is_from_proc_macro(cx, impl_item) {
             self.check_missing_docs_attrs(cx, impl_item.owner_id.def_id, attrs, impl_item.span, article, desc);
         }
+        self.prev_span = Some(impl_item.span);
     }
 
     fn check_field_def(&mut self, cx: &LateContext<'tcx>, sf: &'tcx hir::FieldDef<'_>) {
@@ -208,6 +253,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
                 self.check_missing_docs_attrs(cx, sf.def_id, attrs, sf.span, "a", "struct field");
             }
         }
+        self.prev_span = Some(sf.span);
     }
 
     fn check_variant(&mut self, cx: &LateContext<'tcx>, v: &'tcx hir::Variant<'_>) {
@@ -215,5 +261,13 @@ impl<'tcx> LateLintPass<'tcx> for MissingDoc {
         if !is_from_proc_macro(cx, v) {
             self.check_missing_docs_attrs(cx, v.def_id, attrs, v.span, "a", "variant");
         }
+        self.prev_span = Some(v.span);
     }
 }
+
+fn span_to_snippet_contains_docs(cx: &LateContext<'_>, search_span: Span) -> bool {
+    let Some(snippet) = snippet_opt(cx, search_span) else {
+        return false;
+    };
+    snippet.lines().rev().any(|line| line.trim().starts_with("///"))
+}
diff --git a/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs b/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs
index 70fd07cd93c..648d780ac09 100644
--- a/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs
+++ b/src/tools/clippy/clippy_lints/src/multiple_unsafe_ops_per_block.rs
@@ -109,7 +109,14 @@ fn collect_unsafe_exprs<'tcx>(
             ExprKind::Path(QPath::Resolved(
                 _,
                 hir::Path {
-                    res: Res::Def(DefKind::Static{mutability:Mutability::Mut, ..}, _),
+                    res:
+                        Res::Def(
+                            DefKind::Static {
+                                mutability: Mutability::Mut,
+                                ..
+                            },
+                            _,
+                        ),
                     ..
                 },
             )) => {
@@ -149,7 +156,13 @@ fn collect_unsafe_exprs<'tcx>(
                     ExprKind::Path(QPath::Resolved(
                         _,
                         hir::Path {
-                            res: Res::Def(DefKind::Static{mutability:Mutability::Mut, ..}, _),
+                            res: Res::Def(
+                                DefKind::Static {
+                                    mutability: Mutability::Mut,
+                                    ..
+                                },
+                                _
+                            ),
                             ..
                         }
                     ))
diff --git a/src/tools/clippy/clippy_lints/src/mut_mut.rs b/src/tools/clippy/clippy_lints/src/mut_mut.rs
index 72a2cca1e40..bc7b2c6b7c1 100644
--- a/src/tools/clippy/clippy_lints/src/mut_mut.rs
+++ b/src/tools/clippy/clippy_lints/src/mut_mut.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::span_lint;
+use clippy_utils::diagnostics::{span_lint, span_lint_hir};
 use clippy_utils::higher;
 use rustc_hir as hir;
 use rustc_hir::intravisit;
@@ -35,9 +35,34 @@ impl<'tcx> LateLintPass<'tcx> for MutMut {
     }
 
     fn check_ty(&mut self, cx: &LateContext<'tcx>, ty: &'tcx hir::Ty<'_>) {
-        use rustc_hir::intravisit::Visitor;
+        if in_external_macro(cx.sess(), ty.span) {
+            return;
+        }
 
-        MutVisitor { cx }.visit_ty(ty);
+        if let hir::TyKind::Ref(
+            _,
+            hir::MutTy {
+                ty: pty,
+                mutbl: hir::Mutability::Mut,
+            },
+        ) = ty.kind
+        {
+            if let hir::TyKind::Ref(
+                _,
+                hir::MutTy {
+                    mutbl: hir::Mutability::Mut,
+                    ..
+                },
+            ) = pty.kind
+            {
+                span_lint(
+                    cx,
+                    MUT_MUT,
+                    ty.span,
+                    "generally you want to avoid `&mut &mut _` if possible",
+                );
+            }
+        }
     }
 }
 
@@ -62,17 +87,19 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for MutVisitor<'a, 'tcx> {
             intravisit::walk_expr(self, body);
         } else if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, e) = expr.kind {
             if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, hir::Mutability::Mut, _) = e.kind {
-                span_lint(
+                span_lint_hir(
                     self.cx,
                     MUT_MUT,
+                    expr.hir_id,
                     expr.span,
                     "generally you want to avoid `&mut &mut _` if possible",
                 );
             } else if let ty::Ref(_, ty, hir::Mutability::Mut) = self.cx.typeck_results().expr_ty(e).kind() {
                 if ty.peel_refs().is_sized(self.cx.tcx, self.cx.param_env) {
-                    span_lint(
+                    span_lint_hir(
                         self.cx,
                         MUT_MUT,
+                        expr.hir_id,
                         expr.span,
                         "this expression mutably borrows a mutable reference. Consider reborrowing",
                     );
@@ -80,37 +107,4 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for MutVisitor<'a, 'tcx> {
             }
         }
     }
-
-    fn visit_ty(&mut self, ty: &'tcx hir::Ty<'_>) {
-        if in_external_macro(self.cx.sess(), ty.span) {
-            return;
-        }
-
-        if let hir::TyKind::Ref(
-            _,
-            hir::MutTy {
-                ty: pty,
-                mutbl: hir::Mutability::Mut,
-            },
-        ) = ty.kind
-        {
-            if let hir::TyKind::Ref(
-                _,
-                hir::MutTy {
-                    mutbl: hir::Mutability::Mut,
-                    ..
-                },
-            ) = pty.kind
-            {
-                span_lint(
-                    self.cx,
-                    MUT_MUT,
-                    ty.span,
-                    "generally you want to avoid `&mut &mut _` if possible",
-                );
-            }
-        }
-
-        intravisit::walk_ty(self, ty);
-    }
 }
diff --git a/src/tools/clippy/clippy_lints/src/non_copy_const.rs b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
index cebd2385656..6cb84bb78b6 100644
--- a/src/tools/clippy/clippy_lints/src/non_copy_const.rs
+++ b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
@@ -290,14 +290,21 @@ impl NonCopyConst {
             promoted: None,
         };
         let param_env = cx.tcx.param_env(def_id).with_reveal_all_normalized(cx.tcx);
-        let result = cx.tcx.const_eval_global_id_for_typeck(param_env, cid, rustc_span::DUMMY_SP);
+        let result = cx
+            .tcx
+            .const_eval_global_id_for_typeck(param_env, cid, rustc_span::DUMMY_SP);
         self.is_value_unfrozen_raw(cx, result, ty)
     }
 
     fn is_value_unfrozen_expr<'tcx>(&self, cx: &LateContext<'tcx>, hir_id: HirId, def_id: DefId, ty: Ty<'tcx>) -> bool {
         let args = cx.typeck_results().node_args(hir_id);
 
-        let result = Self::const_eval_resolve(cx.tcx, cx.param_env, ty::UnevaluatedConst::new(def_id, args), rustc_span::DUMMY_SP);
+        let result = Self::const_eval_resolve(
+            cx.tcx,
+            cx.param_env,
+            ty::UnevaluatedConst::new(def_id, args),
+            rustc_span::DUMMY_SP,
+        );
         self.is_value_unfrozen_raw(cx, result, ty)
     }
 
diff --git a/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs b/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs
index fbca4329342..127801de7de 100644
--- a/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs
+++ b/src/tools/clippy/clippy_lints/src/pattern_type_mismatch.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use rustc_hir::{intravisit, Body, Expr, ExprKind, FnDecl, Let, LocalSource, Mutability, Pat, PatKind, Stmt, StmtKind};
+use rustc_hir::{intravisit, Body, Expr, ExprKind, FnDecl, LetExpr, LocalSource, Mutability, Pat, PatKind, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty;
@@ -103,7 +103,7 @@ impl<'tcx> LateLintPass<'tcx> for PatternTypeMismatch {
                 }
             }
         }
-        if let ExprKind::Let(Let { pat, .. }) = expr.kind {
+        if let ExprKind::Let(LetExpr { pat, .. }) = expr.kind {
             apply_lint(cx, pat, DerefPossible::Possible);
         }
     }
diff --git a/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs b/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs
index d0b37cd92e0..0ebdb031d5a 100644
--- a/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs
+++ b/src/tools/clippy/clippy_lints/src/read_zero_byte_vec.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
+use clippy_utils::diagnostics::{span_lint_hir, span_lint_hir_and_then};
 use clippy_utils::get_enclosing_block;
 use clippy_utils::higher::{get_vec_init_kind, VecInitKind};
 use clippy_utils::source::snippet;
@@ -77,37 +77,53 @@ impl<'tcx> LateLintPass<'tcx> for ReadZeroByteVec {
                 if let Some(expr) = visitor.read_zero_expr {
                     let applicability = Applicability::MaybeIncorrect;
                     match vec_init_kind {
-                        VecInitKind::WithConstCapacity(len) => {
-                            span_lint_and_sugg(
+                        VecInitKind::WithConstCapacity(len) => span_lint_hir_and_then(
+                            cx,
+                            READ_ZERO_BYTE_VEC,
+                            expr.hir_id,
+                            expr.span,
+                            "reading zero byte data to `Vec`",
+                            |diag| {
+                                diag.span_suggestion(
+                                    expr.span,
+                                    "try",
+                                    format!("{}.resize({len}, 0); {}", ident.as_str(), snippet(cx, expr.span, "..")),
+                                    applicability,
+                                );
+                            },
+                        ),
+                        VecInitKind::WithExprCapacity(hir_id) => {
+                            let e = cx.tcx.hir().expect_expr(hir_id);
+                            span_lint_hir_and_then(
                                 cx,
                                 READ_ZERO_BYTE_VEC,
+                                expr.hir_id,
                                 expr.span,
                                 "reading zero byte data to `Vec`",
-                                "try",
-                                format!("{}.resize({len}, 0); {}", ident.as_str(), snippet(cx, expr.span, "..")),
-                                applicability,
+                                |diag| {
+                                    diag.span_suggestion(
+                                        expr.span,
+                                        "try",
+                                        format!(
+                                            "{}.resize({}, 0); {}",
+                                            ident.as_str(),
+                                            snippet(cx, e.span, ".."),
+                                            snippet(cx, expr.span, "..")
+                                        ),
+                                        applicability,
+                                    );
+                                },
                             );
                         },
-                        VecInitKind::WithExprCapacity(hir_id) => {
-                            let e = cx.tcx.hir().expect_expr(hir_id);
-                            span_lint_and_sugg(
+                        _ => {
+                            span_lint_hir(
                                 cx,
                                 READ_ZERO_BYTE_VEC,
+                                expr.hir_id,
                                 expr.span,
                                 "reading zero byte data to `Vec`",
-                                "try",
-                                format!(
-                                    "{}.resize({}, 0); {}",
-                                    ident.as_str(),
-                                    snippet(cx, e.span, ".."),
-                                    snippet(cx, expr.span, "..")
-                                ),
-                                applicability,
                             );
                         },
-                        _ => {
-                            span_lint(cx, READ_ZERO_BYTE_VEC, expr.span, "reading zero byte data to `Vec`");
-                        },
                     }
                 }
             }
diff --git a/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs b/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
index c2673bc409f..435899ddaa7 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_closure_call.rs
@@ -1,5 +1,5 @@
 use crate::rustc_lint::LintContext;
-use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
+use clippy_utils::diagnostics::{span_lint_and_then, span_lint_hir};
 use clippy_utils::get_parent_expr;
 use clippy_utils::sugg::Sugg;
 use hir::Param;
@@ -273,9 +273,10 @@ impl<'tcx> LateLintPass<'tcx> for RedundantClosureCall {
                 && ident == path.segments[0].ident
                 && count_closure_usage(cx, block, path) == 1
             {
-                span_lint(
+                span_lint_hir(
                     cx,
                     REDUNDANT_CLOSURE_CALL,
+                    second.hir_id,
                     second.span,
                     "closure called just once immediately after it was declared",
                 );
diff --git a/src/tools/clippy/clippy_lints/src/redundant_else.rs b/src/tools/clippy/clippy_lints/src/redundant_else.rs
index fb434fb7450..3bdf13dbbea 100644
--- a/src/tools/clippy/clippy_lints/src/redundant_else.rs
+++ b/src/tools/clippy/clippy_lints/src/redundant_else.rs
@@ -105,7 +105,7 @@ impl<'ast> Visitor<'ast> for BreakVisitor {
     fn visit_expr(&mut self, expr: &'ast Expr) {
         self.is_break = match expr.kind {
             ExprKind::Break(..) | ExprKind::Continue(..) | ExprKind::Ret(..) => true,
-            ExprKind::Match(_, ref arms) => arms.iter().all(|arm|
+            ExprKind::Match(_, ref arms, _) => arms.iter().all(|arm|
                 arm.body.is_none() || arm.body.as_deref().is_some_and(|body| self.check_expr(body))
             ),
             ExprKind::If(_, ref then, Some(ref els)) => self.check_block(then) && self.check_expr(els),
diff --git a/src/tools/clippy/clippy_lints/src/returns.rs b/src/tools/clippy/clippy_lints/src/returns.rs
index 19697527467..8bc24eda465 100644
--- a/src/tools/clippy/clippy_lints/src/returns.rs
+++ b/src/tools/clippy/clippy_lints/src/returns.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then, span_lint_hir_and_then};
+use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_hir_and_then};
 use clippy_utils::source::{snippet_opt, snippet_with_context};
 use clippy_utils::sugg::has_enclosing_paren;
 use clippy_utils::visitors::{for_each_expr_with_closures, Descend};
@@ -380,7 +380,7 @@ fn check_final_expr<'tcx>(
                 return;
             }
 
-            emit_return_lint(cx, ret_span, semi_spans, &replacement);
+            emit_return_lint(cx, ret_span, semi_spans, &replacement, expr.hir_id);
         },
         ExprKind::If(_, then, else_clause_opt) => {
             check_block_return(cx, &then.kind, peeled_drop_expr.span, semi_spans.clone());
@@ -415,18 +415,31 @@ fn expr_contains_conjunctive_ifs<'tcx>(expr: &'tcx Expr<'tcx>) -> bool {
     contains_if(expr, false)
 }
 
-fn emit_return_lint(cx: &LateContext<'_>, ret_span: Span, semi_spans: Vec<Span>, replacement: &RetReplacement<'_>) {
+fn emit_return_lint(
+    cx: &LateContext<'_>,
+    ret_span: Span,
+    semi_spans: Vec<Span>,
+    replacement: &RetReplacement<'_>,
+    at: HirId,
+) {
     if ret_span.from_expansion() {
         return;
     }
 
-    span_lint_and_then(cx, NEEDLESS_RETURN, ret_span, "unneeded `return` statement", |diag| {
-        let suggestions = std::iter::once((ret_span, replacement.to_string()))
-            .chain(semi_spans.into_iter().map(|span| (span, String::new())))
-            .collect();
+    span_lint_hir_and_then(
+        cx,
+        NEEDLESS_RETURN,
+        at,
+        ret_span,
+        "unneeded `return` statement",
+        |diag| {
+            let suggestions = std::iter::once((ret_span, replacement.to_string()))
+                .chain(semi_spans.into_iter().map(|span| (span, String::new())))
+                .collect();
 
-        diag.multipart_suggestion_verbose(replacement.sugg_help(), suggestions, replacement.applicability());
-    });
+            diag.multipart_suggestion_verbose(replacement.sugg_help(), suggestions, replacement.applicability());
+        },
+    );
 }
 
 fn last_statement_borrows<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) -> bool {
@@ -452,8 +465,8 @@ fn last_statement_borrows<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>)
 // Go backwards while encountering whitespace and extend the given Span to that point.
 fn extend_span_to_previous_non_ws(cx: &LateContext<'_>, sp: Span) -> Span {
     if let Ok(prev_source) = cx.sess().source_map().span_to_prev_source(sp) {
-        let ws = [' ', '\t', '\n'];
-        if let Some(non_ws_pos) = prev_source.rfind(|c| !ws.contains(&c)) {
+        let ws = [b' ', b'\t', b'\n'];
+        if let Some(non_ws_pos) = prev_source.bytes().rposition(|c| !ws.contains(&c)) {
             let len = prev_source.len() - non_ws_pos - 1;
             return sp.with_lo(sp.lo() - BytePos::from_usize(len));
         }
diff --git a/src/tools/clippy/clippy_lints/src/shadow.rs b/src/tools/clippy/clippy_lints/src/shadow.rs
index c74364d89d6..df7bd4c8d1d 100644
--- a/src/tools/clippy/clippy_lints/src/shadow.rs
+++ b/src/tools/clippy/clippy_lints/src/shadow.rs
@@ -5,7 +5,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::hir_id::ItemLocalId;
-use rustc_hir::{Block, Body, BodyOwnerKind, Expr, ExprKind, HirId, Let, Node, Pat, PatKind, QPath, UnOp};
+use rustc_hir::{Block, Body, BodyOwnerKind, Expr, ExprKind, HirId, LetExpr, Node, Pat, PatKind, QPath, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::impl_lint_pass;
 use rustc_span::{Span, Symbol};
@@ -238,7 +238,7 @@ fn find_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'
         let init = match node {
             Node::Arm(_) | Node::Pat(_) => continue,
             Node::Expr(expr) => match expr.kind {
-                ExprKind::Match(e, _, _) | ExprKind::Let(&Let { init: e, .. }) => Some(e),
+                ExprKind::Match(e, _, _) | ExprKind::Let(&LetExpr { init: e, .. }) => Some(e),
                 _ => None,
             },
             Node::Local(local) => local.init,
diff --git a/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs b/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs
index c0e4f3c368a..cf839941123 100644
--- a/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs
+++ b/src/tools/clippy/clippy_lints/src/std_instead_of_core.rs
@@ -109,6 +109,7 @@ impl<'tcx> LateLintPass<'tcx> for StdReexports {
                     sym::core => (STD_INSTEAD_OF_CORE, "std", "core"),
                     sym::alloc => (STD_INSTEAD_OF_ALLOC, "std", "alloc"),
                     _ => {
+                        self.prev_span = first_segment.ident.span;
                         return;
                     },
                 },
@@ -116,6 +117,7 @@ impl<'tcx> LateLintPass<'tcx> for StdReexports {
                     if cx.tcx.crate_name(def_id.krate) == sym::core {
                         (ALLOC_INSTEAD_OF_CORE, "alloc", "core")
                     } else {
+                        self.prev_span = first_segment.ident.span;
                         return;
                     }
                 },
diff --git a/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs b/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
index 60e9d262e7e..ab1b3043f0c 100644
--- a/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
+++ b/src/tools/clippy/clippy_lints/src/suspicious_operation_groupings.rs
@@ -552,7 +552,7 @@ fn ident_difference_expr_with_base_location(
         | (Gen(_, _, _), Gen(_, _, _))
         | (Block(_, _), Block(_, _))
         | (Closure(_), Closure(_))
-        | (Match(_, _), Match(_, _))
+        | (Match(_, _, _), Match(_, _, _))
         | (Loop(_, _, _), Loop(_, _, _))
         | (ForLoop { .. }, ForLoop { .. })
         | (While(_, _, _), While(_, _, _))
diff --git a/src/tools/clippy/clippy_lints/src/thread_local_initializer_can_be_made_const.rs b/src/tools/clippy/clippy_lints/src/thread_local_initializer_can_be_made_const.rs
index 1af3733ebfa..f8bdb866ca3 100644
--- a/src/tools/clippy/clippy_lints/src/thread_local_initializer_can_be_made_const.rs
+++ b/src/tools/clippy/clippy_lints/src/thread_local_initializer_can_be_made_const.rs
@@ -37,7 +37,7 @@ declare_clippy_lint! {
     ///     static BUF: String = const { String::new() };
     /// }
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub THREAD_LOCAL_INITIALIZER_CAN_BE_MADE_CONST,
     perf,
     "suggest using `const` in `thread_local!` macro"
diff --git a/src/tools/clippy/clippy_lints/src/transmute/mod.rs b/src/tools/clippy/clippy_lints/src/transmute/mod.rs
index e47b14bf63b..3c11b481310 100644
--- a/src/tools/clippy/clippy_lints/src/transmute/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/transmute/mod.rs
@@ -514,7 +514,7 @@ declare_clippy_lint! {
     ///              ^^^^ ^^ `bool::then` only executes the closure if the condition is true!
     /// }
     /// ```
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub EAGER_TRANSMUTE,
     correctness,
     "eager evaluation of `transmute`"
diff --git a/src/tools/clippy/clippy_lints/src/types/mod.rs b/src/tools/clippy/clippy_lints/src/types/mod.rs
index bdef82e9c5e..2ad15ac8312 100644
--- a/src/tools/clippy/clippy_lints/src/types/mod.rs
+++ b/src/tools/clippy/clippy_lints/src/types/mod.rs
@@ -392,6 +392,10 @@ impl<'tcx> LateLintPass<'tcx> for Types {
     }
 
     fn check_field_def(&mut self, cx: &LateContext<'tcx>, field: &hir::FieldDef<'tcx>) {
+        if field.span.from_expansion() {
+            return;
+        }
+
         let is_exported = cx.effective_visibilities.is_exported(field.def_id);
 
         self.check_ty(
diff --git a/src/tools/clippy/clippy_lints/src/unconditional_recursion.rs b/src/tools/clippy/clippy_lints/src/unconditional_recursion.rs
index 224ec475c51..d638af2b78b 100644
--- a/src/tools/clippy/clippy_lints/src/unconditional_recursion.rs
+++ b/src/tools/clippy/clippy_lints/src/unconditional_recursion.rs
@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::{expr_or_init, get_trait_def_id, path_def_id};
+use clippy_utils::{expr_or_init, fn_def_id_with_node_args, path_def_id};
 use rustc_ast::BinOpKind;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
@@ -19,11 +19,11 @@ use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor;
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks that there isn't an infinite recursion in `PartialEq` trait
-    /// implementation.
+    /// Checks that there isn't an infinite recursion in trait
+    /// implementations.
     ///
     /// ### Why is this bad?
-    /// This is a hard to find infinite recursion which will crashing any code
+    /// This is a hard to find infinite recursion that will crash any code.
     /// using it.
     ///
     /// ### Example
@@ -42,7 +42,7 @@ declare_clippy_lint! {
     /// Use instead:
     ///
     /// In such cases, either use `#[derive(PartialEq)]` or don't implement it.
-    #[clippy::version = "1.76.0"]
+    #[clippy::version = "1.77.0"]
     pub UNCONDITIONAL_RECURSION,
     suspicious,
     "detect unconditional recursion in some traits implementation"
@@ -201,7 +201,6 @@ fn check_partial_eq(cx: &LateContext<'_>, method_span: Span, method_def_id: Loca
     }
 }
 
-#[allow(clippy::unnecessary_def_path)]
 fn check_to_string(cx: &LateContext<'_>, method_span: Span, method_def_id: LocalDefId, name: Ident, expr: &Expr<'_>) {
     let args = cx
         .tcx
@@ -224,7 +223,7 @@ fn check_to_string(cx: &LateContext<'_>, method_span: Span, method_def_id: Local
         && let Some(trait_) = impl_.of_trait
         && let Some(trait_def_id) = trait_.trait_def_id()
         // The trait is `ToString`.
-        && Some(trait_def_id) == get_trait_def_id(cx, &["alloc", "string", "ToString"])
+        && cx.tcx.is_diagnostic_item(sym::ToString, trait_def_id)
     {
         let is_bad = match expr.kind {
             ExprKind::MethodCall(segment, _receiver, &[_arg], _) if segment.ident.name == name.name => {
@@ -291,7 +290,6 @@ where
         self.map
     }
 
-    #[allow(clippy::unnecessary_def_path)]
     fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
         if self.found_default_call {
             return;
@@ -303,7 +301,7 @@ where
             && is_default_method_on_current_ty(self.cx.tcx, qpath, self.implemented_ty_id)
             && let Some(method_def_id) = path_def_id(self.cx, f)
             && let Some(trait_def_id) = self.cx.tcx.trait_of_item(method_def_id)
-            && Some(trait_def_id) == get_trait_def_id(self.cx, &["core", "default", "Default"])
+            && self.cx.tcx.is_diagnostic_item(sym::Default, trait_def_id)
         {
             self.found_default_call = true;
             span_error(self.cx, self.method_span, expr);
@@ -312,10 +310,9 @@ where
 }
 
 impl UnconditionalRecursion {
-    #[allow(clippy::unnecessary_def_path)]
     fn init_default_impl_for_type_if_needed(&mut self, cx: &LateContext<'_>) {
         if self.default_impl_for_type.is_empty()
-            && let Some(default_trait_id) = get_trait_def_id(cx, &["core", "default", "Default"])
+            && let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default)
         {
             let impls = cx.tcx.trait_impls_of(default_trait_id);
             for (ty, impl_def_ids) in impls.non_blanket_impls() {
@@ -394,6 +391,34 @@ impl UnconditionalRecursion {
     }
 }
 
+fn check_from(cx: &LateContext<'_>, method_span: Span, method_def_id: LocalDefId, expr: &Expr<'_>) {
+    let Some(sig) = cx
+        .typeck_results()
+        .liberated_fn_sigs()
+        .get(cx.tcx.local_def_id_to_hir_id(method_def_id))
+    else {
+        return;
+    };
+
+    // Check if we are calling `Into::into` where the node args match with our `From::from` signature:
+    // From::from signature: fn(S1) -> S2
+    // <S1 as Into<S2>>::into(s1), node_args=[S1, S2]
+    // If they do match, then it must mean that it is the blanket impl,
+    // which calls back into our `From::from` again (`Into` is not specializable).
+    // rustc's unconditional_recursion already catches calling `From::from` directly
+    if let Some((fn_def_id, node_args)) = fn_def_id_with_node_args(cx, expr)
+        && let [s1, s2] = **node_args
+        && let (Some(s1), Some(s2)) = (s1.as_type(), s2.as_type())
+        && let Some(trait_def_id) = cx.tcx.trait_of_item(fn_def_id)
+        && cx.tcx.is_diagnostic_item(sym::Into, trait_def_id)
+        && get_impl_trait_def_id(cx, method_def_id) == cx.tcx.get_diagnostic_item(sym::From)
+        && s1 == sig.inputs()[0]
+        && s2 == sig.output()
+    {
+        span_error(cx, method_span, expr);
+    }
+}
+
 impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
     fn check_fn(
         &mut self,
@@ -410,10 +435,11 @@ impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
             // Doesn't have a conditional return.
             && !has_conditional_return(body, expr)
         {
-            if name.name == sym::eq || name.name == sym::ne {
-                check_partial_eq(cx, method_span, method_def_id, name, expr);
-            } else if name.name == sym::to_string {
-                check_to_string(cx, method_span, method_def_id, name, expr);
+            match name.name {
+                sym::eq | sym::ne => check_partial_eq(cx, method_span, method_def_id, name, expr),
+                sym::to_string => check_to_string(cx, method_span, method_def_id, name, expr),
+                sym::from => check_from(cx, method_span, method_def_id, expr),
+                _ => {},
             }
             self.check_default_new(cx, decl, body, method_span, method_def_id);
         }
diff --git a/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs b/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
index 7246214f9bf..d4dd31e1178 100644
--- a/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
+++ b/src/tools/clippy/clippy_lints/src/unnested_or_patterns.rs
@@ -242,6 +242,8 @@ fn transform_with_focus_on_idx(alternatives: &mut ThinVec<P<Pat>>, focus_idx: us
             |k| matches!(k, Box(_)),
             |k| always_pat!(k, Box(p) => p),
         ),
+        // FIXME(deref_patterns): Should we merge patterns here?
+        Deref(_) => false,
         // Transform `&mut x | ... | &mut y` into `&mut (x | y)`.
         Ref(target, Mutability::Mut) => extend_with_matching(
             target, start, alternatives,
diff --git a/src/tools/clippy/clippy_lints/src/unused_io_amount.rs b/src/tools/clippy/clippy_lints/src/unused_io_amount.rs
index eb64dd633f6..d8c5f1b7382 100644
--- a/src/tools/clippy/clippy_lints/src/unused_io_amount.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_io_amount.rs
@@ -1,7 +1,7 @@
-use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::diagnostics::span_lint_hir_and_then;
 use clippy_utils::macros::{is_panic, root_macro_call_first_node};
 use clippy_utils::{is_res_lang_ctor, is_trait_method, match_trait_method, paths, peel_blocks};
-use hir::{ExprKind, PatKind};
+use hir::{ExprKind, HirId, PatKind};
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
@@ -131,26 +131,26 @@ fn non_consuming_ok_arm<'a>(cx: &LateContext<'a>, arm: &hir::Arm<'a>) -> bool {
 fn check_expr<'a>(cx: &LateContext<'a>, expr: &'a hir::Expr<'a>) {
     match expr.kind {
         hir::ExprKind::If(cond, _, _)
-            if let ExprKind::Let(hir::Let { pat, init, .. }) = cond.kind
+            if let ExprKind::Let(hir::LetExpr { pat, init, .. }) = cond.kind
                 && is_ok_wild_or_dotdot_pattern(cx, pat)
                 && let Some(op) = should_lint(cx, init) =>
         {
-            emit_lint(cx, cond.span, op, &[pat.span]);
+            emit_lint(cx, cond.span, cond.hir_id, op, &[pat.span]);
         },
         // we will capture only the case where the match is Ok( ) or Err( )
         // prefer to match the minimum possible, and expand later if needed
         // to avoid false positives on something as used as this
         hir::ExprKind::Match(expr, [arm1, arm2], hir::MatchSource::Normal) if let Some(op) = should_lint(cx, expr) => {
             if non_consuming_ok_arm(cx, arm1) && non_consuming_err_arm(cx, arm2) {
-                emit_lint(cx, expr.span, op, &[arm1.pat.span]);
+                emit_lint(cx, expr.span, expr.hir_id, op, &[arm1.pat.span]);
             }
             if non_consuming_ok_arm(cx, arm2) && non_consuming_err_arm(cx, arm1) {
-                emit_lint(cx, expr.span, op, &[arm2.pat.span]);
+                emit_lint(cx, expr.span, expr.hir_id, op, &[arm2.pat.span]);
             }
         },
         hir::ExprKind::Match(_, _, hir::MatchSource::Normal) => {},
         _ if let Some(op) = should_lint(cx, expr) => {
-            emit_lint(cx, expr.span, op, &[]);
+            emit_lint(cx, expr.span, expr.hir_id, op, &[]);
         },
         _ => {},
     };
@@ -279,7 +279,7 @@ fn check_io_mode(cx: &LateContext<'_>, call: &hir::Expr<'_>) -> Option<IoOp> {
     }
 }
 
-fn emit_lint(cx: &LateContext<'_>, span: Span, op: IoOp, wild_cards: &[Span]) {
+fn emit_lint(cx: &LateContext<'_>, span: Span, at: HirId, op: IoOp, wild_cards: &[Span]) {
     let (msg, help) = match op {
         IoOp::AsyncRead(false) => (
             "read amount is not handled",
@@ -301,7 +301,7 @@ fn emit_lint(cx: &LateContext<'_>, span: Span, op: IoOp, wild_cards: &[Span]) {
         IoOp::SyncWrite(true) | IoOp::AsyncWrite(true) => ("written amount is not handled", None),
     };
 
-    span_lint_and_then(cx, UNUSED_IO_AMOUNT, span, msg, |diag| {
+    span_lint_hir_and_then(cx, UNUSED_IO_AMOUNT, at, span, msg, |diag| {
         if let Some(help_str) = help {
             diag.help(help_str);
         }
diff --git a/src/tools/clippy/clippy_lints/src/unused_peekable.rs b/src/tools/clippy/clippy_lints/src/unused_peekable.rs
index f1d0c22b1ae..3f4ab3e31cf 100644
--- a/src/tools/clippy/clippy_lints/src/unused_peekable.rs
+++ b/src/tools/clippy/clippy_lints/src/unused_peekable.rs
@@ -1,4 +1,4 @@
-use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_hir_and_then;
 use clippy_utils::ty::{is_type_diagnostic_item, peel_mid_ty_refs_is_mutable};
 use clippy_utils::{fn_def_id, is_trait_method, path_to_local_id, peel_ref_operators};
 use rustc_ast::Mutability;
@@ -79,13 +79,15 @@ impl<'tcx> LateLintPass<'tcx> for UnusedPeekable {
                 }
 
                 if !vis.found_peek_call {
-                    span_lint_and_help(
+                    span_lint_hir_and_then(
                         cx,
                         UNUSED_PEEKABLE,
+                        local.hir_id,
                         ident.span,
                         "`peek` never called on `Peekable` iterator",
-                        None,
-                        "consider removing the call to `peekable`",
+                        |diag| {
+                            diag.help("consider removing the call to `peekable`");
+                        },
                     );
                 }
             }
diff --git a/src/tools/clippy/clippy_lints/src/use_self.rs b/src/tools/clippy/clippy_lints/src/use_self.rs
index a1b08d105b9..b28037db112 100644
--- a/src/tools/clippy/clippy_lints/src/use_self.rs
+++ b/src/tools/clippy/clippy_lints/src/use_self.rs
@@ -8,11 +8,12 @@ use rustc_hir::def::{CtorOf, DefKind, Res};
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::{walk_inf, walk_ty, Visitor};
 use rustc_hir::{
-    self as hir, Expr, ExprKind, FnRetTy, FnSig, GenericArg, GenericArgsParentheses, GenericParam, GenericParamKind,
-    HirId, Impl, ImplItemKind, Item, ItemKind, Pat, PatKind, Path, QPath, Ty, TyKind,
+    self as hir, Expr, ExprKind, FnRetTy, FnSig, GenericArgsParentheses, GenericParam, GenericParamKind, HirId, Impl,
+    ImplItemKind, Item, ItemKind, Pat, PatKind, Path, QPath, Ty, TyKind,
 };
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::Ty as MiddleTy;
 use rustc_session::impl_lint_pass;
 use rustc_span::Span;
 
@@ -95,10 +96,9 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
         let stack_item = if let ItemKind::Impl(Impl { self_ty, generics, .. }) = item.kind
             && let TyKind::Path(QPath::Resolved(_, item_path)) = self_ty.kind
             && let parameters = &item_path.segments.last().expect(SEGMENTS_MSG).args
-            && parameters.as_ref().map_or(true, |params| {
-                params.parenthesized == GenericArgsParentheses::No
-                    && !params.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_)))
-            })
+            && parameters
+                .as_ref()
+                .map_or(true, |params| params.parenthesized == GenericArgsParentheses::No)
             && !item.span.from_expansion()
             && !is_from_proc_macro(cx, item)
         // expensive, should be last check
@@ -226,7 +226,12 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
             } else {
                 hir_ty_to_ty(cx.tcx, hir_ty)
             }
-            && same_type_and_consts(ty, cx.tcx.type_of(impl_id).instantiate_identity())
+            && let impl_ty = cx.tcx.type_of(impl_id).instantiate_identity()
+            && same_type_and_consts(ty, impl_ty)
+            // Ensure the type we encounter and the one from the impl have the same lifetime parameters. It may be that
+            // the lifetime parameters of `ty` are ellided (`impl<'a> Foo<'a> { fn new() -> Self { Foo{..} } }`, in
+            // which case we must still trigger the lint.
+            && (has_no_lifetime(ty) || same_lifetimes(ty, impl_ty))
         {
             span_lint(cx, hir_ty.span);
         }
@@ -318,3 +323,37 @@ fn lint_path_to_variant(cx: &LateContext<'_>, path: &Path<'_>) {
         span_lint(cx, span);
     }
 }
+
+/// Returns `true` if types `a` and `b` have the same lifetime parameters, otherwise returns
+/// `false`.
+///
+/// This function does not check that types `a` and `b` are the same types.
+fn same_lifetimes<'tcx>(a: MiddleTy<'tcx>, b: MiddleTy<'tcx>) -> bool {
+    use rustc_middle::ty::{Adt, GenericArgKind};
+    match (&a.kind(), &b.kind()) {
+        (&Adt(_, args_a), &Adt(_, args_b)) => {
+            args_a
+                .iter()
+                .zip(args_b.iter())
+                .all(|(arg_a, arg_b)| match (arg_a.unpack(), arg_b.unpack()) {
+                    // TODO: Handle inferred lifetimes
+                    (GenericArgKind::Lifetime(inner_a), GenericArgKind::Lifetime(inner_b)) => inner_a == inner_b,
+                    (GenericArgKind::Type(type_a), GenericArgKind::Type(type_b)) => same_lifetimes(type_a, type_b),
+                    _ => true,
+                })
+        },
+        _ => a == b,
+    }
+}
+
+/// Returns `true` if `ty` has no lifetime parameter, otherwise returns `false`.
+fn has_no_lifetime(ty: MiddleTy<'_>) -> bool {
+    use rustc_middle::ty::{Adt, GenericArgKind};
+    match ty.kind() {
+        &Adt(_, args) => !args
+            .iter()
+            // TODO: Handle inferred lifetimes
+            .any(|arg| matches!(arg.unpack(), GenericArgKind::Lifetime(..))),
+        _ => true,
+    }
+}
diff --git a/src/tools/clippy/clippy_lints/src/utils/author.rs b/src/tools/clippy/clippy_lints/src/utils/author.rs
index 187bfda129c..5319915b2ea 100644
--- a/src/tools/clippy/clippy_lints/src/utils/author.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/author.rs
@@ -689,6 +689,11 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 kind!("Box({pat})");
                 self.pat(pat);
             },
+            PatKind::Deref(pat) => {
+                bind!(self, pat);
+                kind!("Deref({pat})");
+                self.pat(pat);
+            },
             PatKind::Ref(pat, muta) => {
                 bind!(self, pat);
                 kind!("Ref({pat}, Mutability::{muta:?})");
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
index 97b509a84f9..1ebe1d6a2c4 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints/metadata_collector.rs
@@ -925,7 +925,7 @@ impl<'a, 'hir> intravisit::Visitor<'hir> for LintResolver<'a, 'hir> {
             && let (expr_ty, _) = walk_ptrs_ty_depth(self.cx.typeck_results().expr_ty(expr))
             && match_type(self.cx, expr_ty, &paths::LINT)
         {
-            if let hir::def::Res::Def(DefKind::Static(..), _) = path.res {
+            if let hir::def::Res::Def(DefKind::Static { .. }, _) = path.res {
                 let lint_name = last_path_segment(qpath).ident.name;
                 self.lints.push(sym_to_string(lint_name).to_ascii_lowercase());
             } else if let Some(local) = get_parent_local(self.cx, expr) {
diff --git a/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs b/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
index 38c832931fc..f4e277fd0c4 100644
--- a/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
+++ b/src/tools/clippy/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
@@ -223,7 +223,7 @@ fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Ve
                     None
                 }
             },
-            Res::Def(DefKind::Static(_), def_id) => read_mir_alloc_def_path(
+            Res::Def(DefKind::Static { .. }, def_id) => read_mir_alloc_def_path(
                 cx,
                 cx.tcx.eval_static_initializer(def_id).ok()?.inner(),
                 cx.tcx.type_of(def_id).instantiate_identity(),
diff --git a/src/tools/clippy/clippy_lints/src/wildcard_imports.rs b/src/tools/clippy/clippy_lints/src/wildcard_imports.rs
index 5410e8ac117..436f0cb79fb 100644
--- a/src/tools/clippy/clippy_lints/src/wildcard_imports.rs
+++ b/src/tools/clippy/clippy_lints/src/wildcard_imports.rs
@@ -213,7 +213,7 @@ fn is_super_only_import(segments: &[PathSegment<'_>]) -> bool {
 // Allow skipping imports containing user configured segments,
 // i.e. "...::utils::...::*" if user put `allowed-wildcard-imports = ["utils"]` in `Clippy.toml`
 fn is_allowed_via_config(segments: &[PathSegment<'_>], allowed_segments: &FxHashSet<String>) -> bool {
-    // segment matching need to be exact instead of using 'contains', in case user unintentionaly put
+    // segment matching need to be exact instead of using 'contains', in case user unintentionally put
     // a single character in the config thus skipping most of the warnings.
     segments.iter().any(|seg| allowed_segments.contains(seg.ident.as_str()))
 }
diff --git a/src/tools/clippy/clippy_lints/src/zero_repeat_side_effects.rs b/src/tools/clippy/clippy_lints/src/zero_repeat_side_effects.rs
new file mode 100644
index 00000000000..852d04cd21b
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/zero_repeat_side_effects.rs
@@ -0,0 +1,154 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher::VecArgs;
+use clippy_utils::source::snippet;
+use clippy_utils::visitors::for_each_expr;
+use rustc_ast::LitKind;
+use rustc_errors::Applicability;
+use rustc_hir::{ExprKind, Node};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::{self, ConstKind, Ty};
+use rustc_session::declare_lint_pass;
+use rustc_span::Span;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for array or vec initializations which call a function or method,
+    /// but which have a repeat count of zero.
+    ///
+    /// ### Why is this bad?
+    /// Such an initialization, despite having a repeat length of 0, will still call the inner function.
+    /// This may not be obvious and as such there may be unintended side effects in code.
+    ///
+    /// ### Example
+    /// ```no_run
+    /// fn side_effect() -> i32 {
+    ///     println!("side effect");
+    ///     10
+    /// }
+    /// let a = [side_effect(); 0];
+    /// ```
+    /// Use instead:
+    /// ```no_run
+    /// fn side_effect() -> i32 {
+    ///     println!("side effect");
+    ///     10
+    /// }
+    /// side_effect();
+    /// let a: [i32; 0] = [];
+    /// ```
+    #[clippy::version = "1.75.0"]
+    pub ZERO_REPEAT_SIDE_EFFECTS,
+    suspicious,
+    "usage of zero-sized initializations of arrays or vecs causing side effects"
+}
+
+declare_lint_pass!(ZeroRepeatSideEffects => [ZERO_REPEAT_SIDE_EFFECTS]);
+
+impl LateLintPass<'_> for ZeroRepeatSideEffects {
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'_ rustc_hir::Expr<'_>) {
+        if let Some(args) = VecArgs::hir(cx, expr)
+            && let VecArgs::Repeat(inner_expr, len) = args
+            && let ExprKind::Lit(l) = len.kind
+            && let LitKind::Int(i, _) = l.node
+            && i.0 == 0
+        {
+            inner_check(cx, expr, inner_expr, true);
+        } else if let ExprKind::Repeat(inner_expr, _) = expr.kind
+            && let ty::Array(_, cst) = cx.typeck_results().expr_ty(expr).kind()
+            && let ConstKind::Value(ty::ValTree::Leaf(element_count)) = cst.kind()
+            && let Ok(element_count) = element_count.try_to_target_usize(cx.tcx)
+            && element_count == 0
+        {
+            inner_check(cx, expr, inner_expr, false);
+        }
+    }
+}
+
+fn inner_check(cx: &LateContext<'_>, expr: &'_ rustc_hir::Expr<'_>, inner_expr: &'_ rustc_hir::Expr<'_>, is_vec: bool) {
+    // check if expr is a call or has a call inside it
+    if for_each_expr(inner_expr, |x| {
+        if let ExprKind::Call(_, _) | ExprKind::MethodCall(_, _, _, _) = x.kind {
+            std::ops::ControlFlow::Break(())
+        } else {
+            std::ops::ControlFlow::Continue(())
+        }
+    })
+    .is_some()
+    {
+        let parent_hir_node = cx.tcx.parent_hir_node(expr.hir_id);
+        let return_type = cx.typeck_results().expr_ty(expr);
+
+        if let Node::Local(l) = parent_hir_node {
+            array_span_lint(
+                cx,
+                l.span,
+                inner_expr.span,
+                l.pat.span,
+                Some(return_type),
+                is_vec,
+                false,
+            );
+        } else if let Node::Expr(x) = parent_hir_node
+            && let ExprKind::Assign(l, _, _) = x.kind
+        {
+            array_span_lint(cx, x.span, inner_expr.span, l.span, Some(return_type), is_vec, true);
+        } else {
+            span_lint_and_sugg(
+                cx,
+                ZERO_REPEAT_SIDE_EFFECTS,
+                expr.span.source_callsite(),
+                "function or method calls as the initial value in zero-sized array initializers may cause side effects",
+                "consider using",
+                format!(
+                    "{{ {}; {}[] as {return_type} }}",
+                    snippet(cx, inner_expr.span.source_callsite(), ".."),
+                    if is_vec { "vec!" } else { "" },
+                ),
+                Applicability::Unspecified,
+            );
+        }
+    }
+}
+
+fn array_span_lint(
+    cx: &LateContext<'_>,
+    expr_span: Span,
+    func_call_span: Span,
+    variable_name_span: Span,
+    expr_ty: Option<Ty<'_>>,
+    is_vec: bool,
+    is_assign: bool,
+) {
+    let has_ty = expr_ty.is_some();
+
+    span_lint_and_sugg(
+        cx,
+        ZERO_REPEAT_SIDE_EFFECTS,
+        expr_span.source_callsite(),
+        "function or method calls as the initial value in zero-sized array initializers may cause side effects",
+        "consider using",
+        format!(
+            "{}; {}{}{} = {}[]{}{}",
+            snippet(cx, func_call_span.source_callsite(), ".."),
+            if has_ty && !is_assign { "let " } else { "" },
+            snippet(cx, variable_name_span.source_callsite(), ".."),
+            if let Some(ty) = expr_ty
+                && !is_assign
+            {
+                format!(": {ty}")
+            } else {
+                String::new()
+            },
+            if is_vec { "vec!" } else { "" },
+            if let Some(ty) = expr_ty
+                && is_assign
+            {
+                format!(" as {ty}")
+            } else {
+                String::new()
+            },
+            if is_assign { "" } else { ";" }
+        ),
+        Applicability::Unspecified,
+    );
+}
diff --git a/src/tools/clippy/clippy_utils/Cargo.toml b/src/tools/clippy/clippy_utils/Cargo.toml
index bf55040ddbc..d2bb719a517 100644
--- a/src/tools/clippy/clippy_utils/Cargo.toml
+++ b/src/tools/clippy/clippy_utils/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "clippy_utils"
-version = "0.1.78"
+version = "0.1.79"
 edition = "2021"
 publish = false
 
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils.rs b/src/tools/clippy/clippy_utils/src/ast_utils.rs
index 3874c1169e4..f7532121aeb 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils.rs
@@ -198,7 +198,7 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         },
         (AssignOp(lo, lp, lv), AssignOp(ro, rp, rv)) => lo.node == ro.node && eq_expr(lp, rp) && eq_expr(lv, rv),
         (Field(lp, lf), Field(rp, rf)) => eq_id(*lf, *rf) && eq_expr(lp, rp),
-        (Match(ls, la), Match(rs, ra)) => eq_expr(ls, rs) && over(la, ra, eq_arm),
+        (Match(ls, la, lkind), Match(rs, ra, rkind)) => (lkind == rkind) && eq_expr(ls, rs) && over(la, ra, eq_arm),
         (
             Closure(box ast::Closure {
                 binder: lb,
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index e75d5953fae..046087d3298 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -10,8 +10,10 @@ use rustc_hir::{BinOp, BinOpKind, Block, ConstBlock, Expr, ExprKind, HirId, Item
 use rustc_lexer::tokenize;
 use rustc_lint::LateContext;
 use rustc_middle::mir::interpret::{alloc_range, Scalar};
+use rustc_middle::mir::ConstValue;
 use rustc_middle::ty::{self, EarlyBinder, FloatTy, GenericArgsRef, IntTy, List, ScalarInt, Ty, TyCtxt, UintTy};
 use rustc_middle::{bug, mir, span_bug};
+use rustc_span::def_id::DefId;
 use rustc_span::symbol::{Ident, Symbol};
 use rustc_span::SyntaxContext;
 use rustc_target::abi::Size;
@@ -307,6 +309,12 @@ impl ConstantSource {
     }
 }
 
+/// Attempts to check whether the expression is a constant representing an empty slice, str, array,
+/// etc…
+pub fn constant_is_empty(lcx: &LateContext<'_>, e: &Expr<'_>) -> Option<bool> {
+    ConstEvalLateContext::new(lcx, lcx.typeck_results()).expr_is_empty(e)
+}
+
 /// Attempts to evaluate the expression as a constant.
 pub fn constant<'tcx>(
     lcx: &LateContext<'tcx>,
@@ -406,7 +414,13 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
         match e.kind {
             ExprKind::ConstBlock(ConstBlock { body, .. }) => self.expr(self.lcx.tcx.hir().body(body).value),
             ExprKind::DropTemps(e) => self.expr(e),
-            ExprKind::Path(ref qpath) => self.fetch_path(qpath, e.hir_id, self.typeck_results.expr_ty(e)),
+            ExprKind::Path(ref qpath) => {
+                self.fetch_path_and_apply(qpath, e.hir_id, self.typeck_results.expr_ty(e), |this, result| {
+                    let result = mir_to_const(this.lcx, result)?;
+                    this.source = ConstantSource::Constant;
+                    Some(result)
+                })
+            },
             ExprKind::Block(block, _) => self.block(block),
             ExprKind::Lit(lit) => {
                 if is_direct_expn_of(e.span, "cfg").is_some() {
@@ -472,6 +486,49 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
         }
     }
 
+    /// Simple constant folding to determine if an expression is an empty slice, str, array, …
+    /// `None` will be returned if the constness cannot be determined, or if the resolution
+    /// leaves the local crate.
+    pub fn expr_is_empty(&mut self, e: &Expr<'_>) -> Option<bool> {
+        match e.kind {
+            ExprKind::ConstBlock(ConstBlock { body, .. }) => self.expr_is_empty(self.lcx.tcx.hir().body(body).value),
+            ExprKind::DropTemps(e) => self.expr_is_empty(e),
+            ExprKind::Path(ref qpath) => {
+                if !self
+                    .typeck_results
+                    .qpath_res(qpath, e.hir_id)
+                    .opt_def_id()
+                    .is_some_and(DefId::is_local)
+                {
+                    return None;
+                }
+                self.fetch_path_and_apply(qpath, e.hir_id, self.typeck_results.expr_ty(e), |this, result| {
+                    mir_is_empty(this.lcx, result)
+                })
+            },
+            ExprKind::Lit(lit) => {
+                if is_direct_expn_of(e.span, "cfg").is_some() {
+                    None
+                } else {
+                    match &lit.node {
+                        LitKind::Str(is, _) => Some(is.is_empty()),
+                        LitKind::ByteStr(s, _) | LitKind::CStr(s, _) => Some(s.is_empty()),
+                        _ => None,
+                    }
+                }
+            },
+            ExprKind::Array(vec) => self.multi(vec).map(|v| v.is_empty()),
+            ExprKind::Repeat(..) => {
+                if let ty::Array(_, n) = self.typeck_results.expr_ty(e).kind() {
+                    Some(n.try_eval_target_usize(self.lcx.tcx, self.lcx.param_env)? == 0)
+                } else {
+                    span_bug!(e.span, "typeck error");
+                }
+            },
+            _ => None,
+        }
+    }
+
     #[expect(clippy::cast_possible_wrap)]
     fn constant_not(&self, o: &Constant<'tcx>, ty: Ty<'_>) -> Option<Constant<'tcx>> {
         use self::Constant::{Bool, Int};
@@ -519,8 +576,11 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
         vec.iter().map(|elem| self.expr(elem)).collect::<Option<_>>()
     }
 
-    /// Lookup a possibly constant expression from an `ExprKind::Path`.
-    fn fetch_path(&mut self, qpath: &QPath<'_>, id: HirId, ty: Ty<'tcx>) -> Option<Constant<'tcx>> {
+    /// Lookup a possibly constant expression from an `ExprKind::Path` and apply a function on it.
+    fn fetch_path_and_apply<T, F>(&mut self, qpath: &QPath<'_>, id: HirId, ty: Ty<'tcx>, f: F) -> Option<T>
+    where
+        F: FnOnce(&mut Self, rustc_middle::mir::Const<'tcx>) -> Option<T>,
+    {
         let res = self.typeck_results.qpath_res(qpath, id);
         match res {
             Res::Def(DefKind::Const | DefKind::AssocConst, def_id) => {
@@ -553,9 +613,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                     .const_eval_resolve(self.param_env, mir::UnevaluatedConst::new(def_id, args), qpath.span())
                     .ok()
                     .map(|val| rustc_middle::mir::Const::from_value(val, ty))?;
-                let result = mir_to_const(self.lcx, result)?;
-                self.source = ConstantSource::Constant;
-                Some(result)
+                f(self, result)
             },
             _ => None,
         }
@@ -746,7 +804,6 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
 }
 
 pub fn mir_to_const<'tcx>(lcx: &LateContext<'tcx>, result: mir::Const<'tcx>) -> Option<Constant<'tcx>> {
-    use rustc_middle::mir::ConstValue;
     let mir::Const::Val(val, _) = result else {
         // We only work on evaluated consts.
         return None;
@@ -794,6 +851,42 @@ pub fn mir_to_const<'tcx>(lcx: &LateContext<'tcx>, result: mir::Const<'tcx>) ->
     }
 }
 
+fn mir_is_empty<'tcx>(lcx: &LateContext<'tcx>, result: mir::Const<'tcx>) -> Option<bool> {
+    let mir::Const::Val(val, _) = result else {
+        // We only work on evaluated consts.
+        return None;
+    };
+    match (val, result.ty().kind()) {
+        (_, ty::Ref(_, inner_ty, _)) => match inner_ty.kind() {
+            ty::Str | ty::Slice(_) => {
+                if let ConstValue::Indirect { alloc_id, offset } = val {
+                    // Get the length from the slice, using the same formula as
+                    // [`ConstValue::try_get_slice_bytes_for_diagnostics`].
+                    let a = lcx.tcx.global_alloc(alloc_id).unwrap_memory().inner();
+                    let ptr_size = lcx.tcx.data_layout.pointer_size;
+                    if a.size() < offset + 2 * ptr_size {
+                        // (partially) dangling reference
+                        return None;
+                    }
+                    let len = a
+                        .read_scalar(&lcx.tcx, alloc_range(offset + ptr_size, ptr_size), false)
+                        .ok()?
+                        .to_target_usize(&lcx.tcx)
+                        .ok()?;
+                    Some(len == 0)
+                } else {
+                    None
+                }
+            },
+            ty::Array(_, len) => Some(len.try_to_target_usize(lcx.tcx)? == 0),
+            _ => None,
+        },
+        (ConstValue::Indirect { .. }, ty::Array(_, len)) => Some(len.try_to_target_usize(lcx.tcx)? == 0),
+        (ConstValue::ZeroSized, _) => Some(true),
+        _ => None,
+    }
+}
+
 fn field_of_struct<'tcx>(
     adt_def: ty::AdtDef<'tcx>,
     lcx: &LateContext<'tcx>,
diff --git a/src/tools/clippy/clippy_utils/src/diagnostics.rs b/src/tools/clippy/clippy_utils/src/diagnostics.rs
index 6ed46e5dde0..0352696f93e 100644
--- a/src/tools/clippy/clippy_utils/src/diagnostics.rs
+++ b/src/tools/clippy/clippy_utils/src/diagnostics.rs
@@ -36,6 +36,20 @@ fn docs_link(diag: &mut Diag<'_, ()>, lint: &'static Lint) {
 /// Usually it's nicer to provide more context for lint messages.
 /// Be sure the output is understandable when you use this method.
 ///
+/// NOTE: Lint emissions are always bound to a node in the HIR, which is used to determine
+/// the lint level.
+/// For the `span_lint` function, the node that was passed into the `LintPass::check_*` function is
+/// used.
+///
+/// If you're emitting the lint at the span of a different node than the one provided by the
+/// `LintPass::check_*` function, consider using [`span_lint_hir`] instead.
+/// This is needed for `#[allow]` and `#[expect]` attributes to work on the node
+/// highlighted in the displayed warning.
+///
+/// If you're unsure which function you should use, you can test if the `#[allow]` attribute works
+/// where you would expect it to.
+/// If it doesn't, you likely need to use [`span_lint_hir`] instead.
+///
 /// # Example
 ///
 /// ```ignore
@@ -61,6 +75,20 @@ pub fn span_lint<T: LintContext>(cx: &T, lint: &'static Lint, sp: impl Into<Mult
 ///
 /// If you change the signature, remember to update the internal lint `CollapsibleCalls`
 ///
+/// NOTE: Lint emissions are always bound to a node in the HIR, which is used to determine
+/// the lint level.
+/// For the `span_lint_and_help` function, the node that was passed into the `LintPass::check_*`
+/// function is used.
+///
+/// If you're emitting the lint at the span of a different node than the one provided by the
+/// `LintPass::check_*` function, consider using [`span_lint_hir_and_then`] instead.
+/// This is needed for `#[allow]` and `#[expect]` attributes to work on the node
+/// highlighted in the displayed warning.
+///
+/// If you're unsure which function you should use, you can test if the `#[allow]` attribute works
+/// where you would expect it to.
+/// If it doesn't, you likely need to use [`span_lint_hir_and_then`] instead.
+///
 /// # Example
 ///
 /// ```text
@@ -99,6 +127,20 @@ pub fn span_lint_and_help<T: LintContext>(
 ///
 /// If you change the signature, remember to update the internal lint `CollapsibleCalls`
 ///
+/// NOTE: Lint emissions are always bound to a node in the HIR, which is used to determine
+/// the lint level.
+/// For the `span_lint_and_note` function, the node that was passed into the `LintPass::check_*`
+/// function is used.
+///
+/// If you're emitting the lint at the span of a different node than the one provided by the
+/// `LintPass::check_*` function, consider using [`span_lint_hir_and_then`] instead.
+/// This is needed for `#[allow]` and `#[expect]` attributes to work on the node
+/// highlighted in the displayed warning.
+///
+/// If you're unsure which function you should use, you can test if the `#[allow]` attribute works
+/// where you would expect it to.
+/// If it doesn't, you likely need to use [`span_lint_hir_and_then`] instead.
+///
 /// # Example
 ///
 /// ```text
@@ -139,6 +181,20 @@ pub fn span_lint_and_note<T: LintContext>(
 ///
 /// If you need to customize your lint output a lot, use this function.
 /// If you change the signature, remember to update the internal lint `CollapsibleCalls`
+///
+/// NOTE: Lint emissions are always bound to a node in the HIR, which is used to determine
+/// the lint level.
+/// For the `span_lint_and_then` function, the node that was passed into the `LintPass::check_*`
+/// function is used.
+///
+/// If you're emitting the lint at the span of a different node than the one provided by the
+/// `LintPass::check_*` function, consider using [`span_lint_hir_and_then`] instead.
+/// This is needed for `#[allow]` and `#[expect]` attributes to work on the node
+/// highlighted in the displayed warning.
+///
+/// If you're unsure which function you should use, you can test if the `#[allow]` attribute works
+/// where you would expect it to.
+/// If it doesn't, you likely need to use [`span_lint_hir_and_then`] instead.
 pub fn span_lint_and_then<C, S, F>(cx: &C, lint: &'static Lint, sp: S, msg: &str, f: F)
 where
     C: LintContext,
@@ -152,6 +208,30 @@ where
     });
 }
 
+/// Like [`span_lint`], but emits the lint at the node identified by the given `HirId`.
+///
+/// This is in contrast to [`span_lint`], which always emits the lint at the node that was last
+/// passed to the `LintPass::check_*` function.
+///
+/// The `HirId` is used for checking lint level attributes and to fulfill lint expectations defined
+/// via the `#[expect]` attribute.
+///
+/// For example:
+/// ```ignore
+/// fn f() { /* <node_1> */
+///
+///     #[allow(clippy::some_lint)]
+///     let _x = /* <expr_1> */;
+/// }
+/// ```
+/// If `some_lint` does its analysis in `LintPass::check_fn` (at `<node_1>`) and emits a lint at
+/// `<expr_1>` using [`span_lint`], then allowing the lint at `<expr_1>` as attempted in the snippet
+/// will not work!
+/// Even though that is where the warning points at, which would be confusing to users.
+///
+/// Instead, use this function and also pass the `HirId` of `<expr_1>`, which will let
+/// the compiler check lint level attributes at the place of the expression and
+/// the `#[allow]` will work.
 pub fn span_lint_hir(cx: &LateContext<'_>, lint: &'static Lint, hir_id: HirId, sp: Span, msg: &str) {
     #[expect(clippy::disallowed_methods)]
     cx.tcx.node_span_lint(lint, hir_id, sp, msg.to_string(), |diag| {
@@ -159,6 +239,30 @@ pub fn span_lint_hir(cx: &LateContext<'_>, lint: &'static Lint, hir_id: HirId, s
     });
 }
 
+/// Like [`span_lint_and_then`], but emits the lint at the node identified by the given `HirId`.
+///
+/// This is in contrast to [`span_lint_and_then`], which always emits the lint at the node that was
+/// last passed to the `LintPass::check_*` function.
+///
+/// The `HirId` is used for checking lint level attributes and to fulfill lint expectations defined
+/// via the `#[expect]` attribute.
+///
+/// For example:
+/// ```ignore
+/// fn f() { /* <node_1> */
+///
+///     #[allow(clippy::some_lint)]
+///     let _x = /* <expr_1> */;
+/// }
+/// ```
+/// If `some_lint` does its analysis in `LintPass::check_fn` (at `<node_1>`) and emits a lint at
+/// `<expr_1>` using [`span_lint`], then allowing the lint at `<expr_1>` as attempted in the snippet
+/// will not work!
+/// Even though that is where the warning points at, which would be confusing to users.
+///
+/// Instead, use this function and also pass the `HirId` of `<expr_1>`, which will let
+/// the compiler check lint level attributes at the place of the expression and
+/// the `#[allow]` will work.
 pub fn span_lint_hir_and_then(
     cx: &LateContext<'_>,
     lint: &'static Lint,
@@ -182,6 +286,20 @@ pub fn span_lint_hir_and_then(
 ///
 /// If you change the signature, remember to update the internal lint `CollapsibleCalls`
 ///
+/// NOTE: Lint emissions are always bound to a node in the HIR, which is used to determine
+/// the lint level.
+/// For the `span_lint_and_sugg` function, the node that was passed into the `LintPass::check_*`
+/// function is used.
+///
+/// If you're emitting the lint at the span of a different node than the one provided by the
+/// `LintPass::check_*` function, consider using [`span_lint_hir_and_then`] instead.
+/// This is needed for `#[allow]` and `#[expect]` attributes to work on the node
+/// highlighted in the displayed warning.
+///
+/// If you're unsure which function you should use, you can test if the `#[allow]` attribute works
+/// where you would expect it to.
+/// If it doesn't, you likely need to use [`span_lint_hir_and_then`] instead.
+///
 /// # Example
 ///
 /// ```text
diff --git a/src/tools/clippy/clippy_utils/src/higher.rs b/src/tools/clippy/clippy_utils/src/higher.rs
index ba682813dad..8ce19998a08 100644
--- a/src/tools/clippy/clippy_utils/src/higher.rs
+++ b/src/tools/clippy/clippy_utils/src/higher.rs
@@ -102,7 +102,7 @@ impl<'hir> IfLet<'hir> {
         if let ExprKind::If(
             Expr {
                 kind:
-                    ExprKind::Let(&hir::Let {
+                    ExprKind::Let(&hir::LetExpr {
                         pat: let_pat,
                         init: let_expr,
                         span: let_span,
@@ -379,7 +379,7 @@ impl<'hir> WhileLet<'hir> {
                             ExprKind::If(
                                 Expr {
                                     kind:
-                                        ExprKind::Let(&hir::Let {
+                                        ExprKind::Let(&hir::LetExpr {
                                             pat: let_pat,
                                             init: let_expr,
                                             span: let_span,
diff --git a/src/tools/clippy/clippy_utils/src/hir_utils.rs b/src/tools/clippy/clippy_utils/src/hir_utils.rs
index 106d1d0d77f..7a4eba9790e 100644
--- a/src/tools/clippy/clippy_utils/src/hir_utils.rs
+++ b/src/tools/clippy/clippy_utils/src/hir_utils.rs
@@ -8,7 +8,7 @@ use rustc_hir::def::Res;
 use rustc_hir::MatchSource::TryDesugar;
 use rustc_hir::{
     ArrayLen, BinOpKind, BindingAnnotation, Block, BodyId, Closure, Expr, ExprField, ExprKind, FnRetTy, GenericArg,
-    GenericArgs, HirId, HirIdMap, InlineAsmOperand, Let, Lifetime, LifetimeName, Pat, PatField, PatKind, Path,
+    GenericArgs, HirId, HirIdMap, InlineAsmOperand, LetExpr, Lifetime, LifetimeName, Pat, PatField, PatKind, Path,
     PathSegment, PrimTy, QPath, Stmt, StmtKind, Ty, TyKind, TypeBinding,
 };
 use rustc_lexer::{tokenize, TokenKind};
@@ -837,7 +837,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                     }
                 }
             },
-            ExprKind::Let(Let { pat, init, ty, .. }) => {
+            ExprKind::Let(LetExpr { pat, init, ty, .. }) => {
                 self.hash_expr(init);
                 if let Some(ty) = ty {
                     self.hash_ty(ty);
@@ -955,6 +955,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 }
             },
             PatKind::Box(pat) => self.hash_pat(pat),
+            PatKind::Deref(pat) => self.hash_pat(pat),
             PatKind::Lit(expr) => self.hash_expr(expr),
             PatKind::Or(pats) => {
                 for pat in pats {
diff --git a/src/tools/clippy/clippy_utils/src/lib.rs b/src/tools/clippy/clippy_utils/src/lib.rs
index a38db0ebec0..11b56ed47de 100644
--- a/src/tools/clippy/clippy_utils/src/lib.rs
+++ b/src/tools/clippy/clippy_utils/src/lib.rs
@@ -1678,7 +1678,7 @@ pub fn is_refutable(cx: &LateContext<'_>, pat: &Pat<'_>) -> bool {
     match pat.kind {
         PatKind::Wild | PatKind::Never => false, // If `!` typechecked then the type is empty, so not refutable.
         PatKind::Binding(_, _, _, pat) => pat.map_or(false, |pat| is_refutable(cx, pat)),
-        PatKind::Box(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
+        PatKind::Box(pat) | PatKind::Deref(pat) | PatKind::Ref(pat, _) => is_refutable(cx, pat),
         PatKind::Path(ref qpath) => is_enum_variant(cx, qpath, pat.hir_id),
         PatKind::Or(pats) => {
             // TODO: should be the honest check, that pats is exhaustive set
@@ -2246,8 +2246,21 @@ pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
 
 /// Returns the `DefId` of the callee if the given expression is a function or method call.
 pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
+    fn_def_id_with_node_args(cx, expr).map(|(did, _)| did)
+}
+
+/// Returns the `DefId` of the callee if the given expression is a function or method call,
+/// as well as its node args.
+pub fn fn_def_id_with_node_args<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &Expr<'_>,
+) -> Option<(DefId, rustc_ty::GenericArgsRef<'tcx>)> {
+    let typeck = cx.typeck_results();
     match &expr.kind {
-        ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
+        ExprKind::MethodCall(..) => Some((
+            typeck.type_dependent_def_id(expr.hir_id)?,
+            typeck.node_args(expr.hir_id),
+        )),
         ExprKind::Call(
             Expr {
                 kind: ExprKind::Path(qpath),
@@ -2259,9 +2272,9 @@ pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
             // Only return Fn-like DefIds, not the DefIds of statics/consts/etc that contain or
             // deref to fn pointers, dyn Fn, impl Fn - #8850
             if let Res::Def(DefKind::Fn | DefKind::Ctor(..) | DefKind::AssocFn, id) =
-                cx.typeck_results().qpath_res(qpath, *path_hir_id)
+                typeck.qpath_res(qpath, *path_hir_id)
             {
-                Some(id)
+                Some((id, typeck.node_args(*path_hir_id)))
             } else {
                 None
             }
diff --git a/src/tools/clippy/clippy_utils/src/paths.rs b/src/tools/clippy/clippy_utils/src/paths.rs
index 987f28192a8..456b8019e95 100644
--- a/src/tools/clippy/clippy_utils/src/paths.rs
+++ b/src/tools/clippy/clippy_utils/src/paths.rs
@@ -19,6 +19,8 @@ pub const BTREESET_ITER: [&str; 6] = ["alloc", "collections", "btree", "set", "B
 pub const CLONE_TRAIT_METHOD: [&str; 4] = ["core", "clone", "Clone", "clone"];
 pub const CORE_ITER_CLONED: [&str; 6] = ["core", "iter", "traits", "iterator", "Iterator", "cloned"];
 pub const CORE_ITER_COPIED: [&str; 6] = ["core", "iter", "traits", "iterator", "Iterator", "copied"];
+pub const CORE_ITER_ENUMERATE_METHOD: [&str; 6] = ["core", "iter", "traits", "iterator", "Iterator", "enumerate"];
+pub const CORE_ITER_ENUMERATE_STRUCT: [&str; 5] = ["core", "iter", "adapters", "enumerate", "Enumerate"];
 pub const CORE_ITER_FILTER: [&str; 6] = ["core", "iter", "traits", "iterator", "Iterator", "filter"];
 pub const CORE_RESULT_OK_METHOD: [&str; 4] = ["core", "result", "Result", "ok"];
 pub const CSTRING_AS_C_STR: [&str; 5] = ["alloc", "ffi", "c_str", "CString", "as_c_str"];
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
index 6e011a28bb7..801452e444c 100644
--- a/src/tools/clippy/clippy_utils/src/ty.rs
+++ b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -96,7 +96,7 @@ pub fn contains_ty_adt_constructor_opaque<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'
                         return false;
                     }
 
-                    for (predicate, _span) in cx.tcx.explicit_item_bounds(def_id).instantiate_identity_iter_copied() {
+                    for (predicate, _span) in cx.tcx.explicit_item_super_predicates(def_id).instantiate_identity_iter_copied() {
                         match predicate.kind().skip_binder() {
                             // For `impl Trait<U>`, it will register a predicate of `T: Trait<U>`, so we go through
                             // and check substitutions to find `U`.
@@ -328,7 +328,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
         },
         ty::Tuple(args) => args.iter().any(|ty| is_must_use_ty(cx, ty)),
         ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => {
-            for (predicate, _) in cx.tcx.explicit_item_bounds(def_id).skip_binder() {
+            for (predicate, _) in cx.tcx.explicit_item_super_predicates(def_id).skip_binder() {
                 if let ty::ClauseKind::Trait(trait_predicate) = predicate.kind().skip_binder() {
                     if cx.tcx.has_attr(trait_predicate.trait_ref.def_id, sym::must_use) {
                         return true;
@@ -729,7 +729,7 @@ pub fn ty_sig<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<ExprFnSig<'t
         ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => sig_from_bounds(
             cx,
             ty,
-            cx.tcx.item_bounds(def_id).iter_instantiated(cx.tcx, args),
+            cx.tcx.item_super_predicates(def_id).iter_instantiated(cx.tcx, args),
             cx.tcx.opt_parent(def_id),
         ),
         ty::FnPtr(sig) => Some(ExprFnSig::Sig(sig, None)),
@@ -807,7 +807,7 @@ fn sig_for_projection<'tcx>(cx: &LateContext<'tcx>, ty: AliasTy<'tcx>) -> Option
 
     for (pred, _) in cx
         .tcx
-        .explicit_item_bounds(ty.def_id)
+        .explicit_item_super_predicates(ty.def_id)
         .iter_instantiated_copied(cx.tcx, ty.args)
     {
         match pred.kind().skip_binder() {
diff --git a/src/tools/clippy/clippy_utils/src/visitors.rs b/src/tools/clippy/clippy_utils/src/visitors.rs
index ebc38e531fe..0a05ac029ea 100644
--- a/src/tools/clippy/clippy_utils/src/visitors.rs
+++ b/src/tools/clippy/clippy_utils/src/visitors.rs
@@ -5,7 +5,7 @@ use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::intravisit::{self, walk_block, walk_expr, Visitor};
 use rustc_hir::{
-    AnonConst, Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, Let, Pat, QPath,
+    AnonConst, Arm, Block, BlockCheckMode, Body, BodyId, Expr, ExprKind, HirId, ItemId, ItemKind, LetExpr, Pat, QPath,
     Stmt, UnOp, UnsafeSource, Unsafety,
 };
 use rustc_lint::LateContext;
@@ -624,7 +624,7 @@ pub fn for_each_unconsumed_temporary<'tcx, B>(
             | ExprKind::Field(e, _)
             | ExprKind::Unary(UnOp::Deref, e)
             | ExprKind::Match(e, ..)
-            | ExprKind::Let(&Let { init: e, .. }) => {
+            | ExprKind::Let(&LetExpr { init: e, .. }) => {
                 helper(typeck, false, e, f)?;
             },
             ExprKind::Block(&Block { expr: Some(e), .. }, _) | ExprKind::Cast(e, _) | ExprKind::Unary(_, e) => {
diff --git a/src/tools/clippy/declare_clippy_lint/Cargo.toml b/src/tools/clippy/declare_clippy_lint/Cargo.toml
index 296eb8dd340..9a3a41e1d1e 100644
--- a/src/tools/clippy/declare_clippy_lint/Cargo.toml
+++ b/src/tools/clippy/declare_clippy_lint/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "declare_clippy_lint"
-version = "0.1.78"
+version = "0.1.79"
 edition = "2021"
 publish = false
 
diff --git a/src/tools/clippy/rust-toolchain b/src/tools/clippy/rust-toolchain
index 070b62887d5..a63e66f3214 100644
--- a/src/tools/clippy/rust-toolchain
+++ b/src/tools/clippy/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2024-03-07"
+channel = "nightly-2024-03-21"
 components = ["cargo", "llvm-tools", "rust-src", "rust-std", "rustc", "rustc-dev", "rustfmt"]
diff --git a/src/tools/clippy/tests/ui-internal/disallow_span_lint.stderr b/src/tools/clippy/tests/ui-internal/disallow_span_lint.stderr
index ae5d6843406..cfc590bed36 100644
--- a/src/tools/clippy/tests/ui-internal/disallow_span_lint.stderr
+++ b/src/tools/clippy/tests/ui-internal/disallow_span_lint.stderr
@@ -4,6 +4,7 @@ error: use of a disallowed method `rustc_lint::context::LintContext::span_lint`
 LL |     cx.span_lint(lint, span, msg, |_| {});
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
+   = note: this function does not add a link to our documentation, please use the `clippy_utils::diagnostics::span_lint*` functions instead (from clippy.toml)
    = note: `-D clippy::disallowed-methods` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::disallowed_methods)]`
 
@@ -12,6 +13,8 @@ error: use of a disallowed method `rustc_middle::ty::context::TyCtxt::node_span_
    |
 LL |     tcx.node_span_lint(lint, hir_id, span, msg, |_| {});
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: this function does not add a link to our documentation, please use the `clippy_utils::diagnostics::span_lint_hir*` functions instead (from clippy.toml)
 
 error: aborting due to 2 previous errors
 
diff --git a/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.fixed b/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.fixed
new file mode 100644
index 00000000000..d42b29ba21a
--- /dev/null
+++ b/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.fixed
@@ -0,0 +1,38 @@
+//@compile-flags: --test
+#![warn(clippy::dbg_macro)]
+#![allow(clippy::unnecessary_operation, clippy::no_effect)]
+
+fn foo(n: u32) -> u32 {
+    if let Some(n) = n.checked_sub(4) { n } else { n }
+}
+
+fn factorial(n: u32) -> u32 {
+    if n <= 1 {
+        1
+    } else {
+        n * factorial(n - 1)
+    }
+}
+
+fn main() {
+    42;
+    foo(3) + factorial(4);
+    (1, 2, 3, 4, 5);
+}
+
+#[test]
+pub fn issue8481() {
+    dbg!(1);
+}
+
+#[cfg(test)]
+fn foo2() {
+    dbg!(1);
+}
+
+#[cfg(test)]
+mod mod1 {
+    fn func() {
+        dbg!(1);
+    }
+}
diff --git a/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.rs b/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.rs
index 67129e62477..bd189b1576f 100644
--- a/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.rs
+++ b/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.rs
@@ -1,6 +1,7 @@
 //@compile-flags: --test
 #![warn(clippy::dbg_macro)]
-//@no-rustfix
+#![allow(clippy::unnecessary_operation, clippy::no_effect)]
+
 fn foo(n: u32) -> u32 {
     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
 }
@@ -15,9 +16,7 @@ fn factorial(n: u32) -> u32 {
 
 fn main() {
     dbg!(42);
-    dbg!(dbg!(dbg!(42)));
     foo(3) + dbg!(factorial(4));
-    dbg!(1, 2, dbg!(3, 4));
     dbg!(1, 2, 3, 4, 5);
 }
 
diff --git a/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.stderr b/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.stderr
index 8ffc426be2d..129fab5ff97 100644
--- a/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.stderr
+++ b/src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.stderr
@@ -1,5 +1,5 @@
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:5:22
+  --> tests/ui-toml/dbg_macro/dbg_macro.rs:6:22
    |
 LL |     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
    |                      ^^^^^^^^^^^^^^^^^^^^^^
@@ -12,7 +12,7 @@ LL |     if let Some(n) = n.checked_sub(4) { n } else { n }
    |                      ~~~~~~~~~~~~~~~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:9:8
+  --> tests/ui-toml/dbg_macro/dbg_macro.rs:10:8
    |
 LL |     if dbg!(n <= 1) {
    |        ^^^^^^^^^^^^
@@ -23,7 +23,7 @@ LL |     if n <= 1 {
    |        ~~~~~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:10:9
+  --> tests/ui-toml/dbg_macro/dbg_macro.rs:11:9
    |
 LL |         dbg!(1)
    |         ^^^^^^^
@@ -34,7 +34,7 @@ LL |         1
    |
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:12:9
+  --> tests/ui-toml/dbg_macro/dbg_macro.rs:13:9
    |
 LL |         dbg!(n * factorial(n - 1))
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -45,7 +45,7 @@ LL |         n * factorial(n - 1)
    |
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:17:5
+  --> tests/ui-toml/dbg_macro/dbg_macro.rs:18:5
    |
 LL |     dbg!(42);
    |     ^^^^^^^^
@@ -56,17 +56,6 @@ LL |     42;
    |     ~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:18:5
-   |
-LL |     dbg!(dbg!(dbg!(42)));
-   |     ^^^^^^^^^^^^^^^^^^^^
-   |
-help: remove the invocation before committing it to a version control system
-   |
-LL |     dbg!(dbg!(42));
-   |     ~~~~~~~~~~~~~~
-
-error: the `dbg!` macro is intended as a debugging tool
   --> tests/ui-toml/dbg_macro/dbg_macro.rs:19:14
    |
 LL |     foo(3) + dbg!(factorial(4));
@@ -80,17 +69,6 @@ LL |     foo(3) + factorial(4);
 error: the `dbg!` macro is intended as a debugging tool
   --> tests/ui-toml/dbg_macro/dbg_macro.rs:20:5
    |
-LL |     dbg!(1, 2, dbg!(3, 4));
-   |     ^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: remove the invocation before committing it to a version control system
-   |
-LL |     (1, 2, dbg!(3, 4));
-   |     ~~~~~~~~~~~~~~~~~~
-
-error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui-toml/dbg_macro/dbg_macro.rs:21:5
-   |
 LL |     dbg!(1, 2, 3, 4, 5);
    |     ^^^^^^^^^^^^^^^^^^^
    |
@@ -99,5 +77,5 @@ help: remove the invocation before committing it to a version control system
 LL |     (1, 2, 3, 4, 5);
    |     ~~~~~~~~~~~~~~~
 
-error: aborting due to 9 previous errors
+error: aborting due to 7 previous errors
 
diff --git a/src/tools/clippy/tests/ui/allow_attributes_without_reason.rs b/src/tools/clippy/tests/ui/allow_attributes_without_reason.rs
index 663c2eb2c37..523148d6586 100644
--- a/src/tools/clippy/tests/ui/allow_attributes_without_reason.rs
+++ b/src/tools/clippy/tests/ui/allow_attributes_without_reason.rs
@@ -1,7 +1,7 @@
 //@aux-build:proc_macros.rs
 #![feature(lint_reasons)]
 #![deny(clippy::allow_attributes_without_reason)]
-#![allow(unfulfilled_lint_expectations)]
+#![allow(unfulfilled_lint_expectations, clippy::duplicated_attributes)]
 
 extern crate proc_macros;
 use proc_macros::{external, with_span};
diff --git a/src/tools/clippy/tests/ui/allow_attributes_without_reason.stderr b/src/tools/clippy/tests/ui/allow_attributes_without_reason.stderr
index 3c81233bf77..770a771ec3d 100644
--- a/src/tools/clippy/tests/ui/allow_attributes_without_reason.stderr
+++ b/src/tools/clippy/tests/ui/allow_attributes_without_reason.stderr
@@ -1,8 +1,8 @@
 error: `allow` attribute without specifying a reason
   --> tests/ui/allow_attributes_without_reason.rs:4:1
    |
-LL | #![allow(unfulfilled_lint_expectations)]
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | #![allow(unfulfilled_lint_expectations, clippy::duplicated_attributes)]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: try adding a reason at the end with `, reason = ".."`
 note: the lint level is defined here
diff --git a/src/tools/clippy/tests/ui/assigning_clones.fixed b/src/tools/clippy/tests/ui/assigning_clones.fixed
index c66e0c1f602..160f3b94663 100644
--- a/src/tools/clippy/tests/ui/assigning_clones.fixed
+++ b/src/tools/clippy/tests/ui/assigning_clones.fixed
@@ -128,6 +128,19 @@ fn ignore_generic_clone<T: Clone>(a: &mut T, b: &T) {
     *a = b.clone();
 }
 
+#[clippy::msrv = "1.62"]
+fn msrv_1_62(mut a: String, b: String, c: &str) {
+    a.clone_from(&b);
+    // Should not be linted, as clone_into wasn't stabilized until 1.63
+    a = c.to_owned();
+}
+
+#[clippy::msrv = "1.63"]
+fn msrv_1_63(mut a: String, b: String, c: &str) {
+    a.clone_from(&b);
+    c.clone_into(&mut a);
+}
+
 macro_rules! clone_inside {
     ($a:expr, $b: expr) => {
         $a = $b.clone();
diff --git a/src/tools/clippy/tests/ui/assigning_clones.rs b/src/tools/clippy/tests/ui/assigning_clones.rs
index b9f994d3e03..14ba1d4db9a 100644
--- a/src/tools/clippy/tests/ui/assigning_clones.rs
+++ b/src/tools/clippy/tests/ui/assigning_clones.rs
@@ -128,6 +128,19 @@ fn ignore_generic_clone<T: Clone>(a: &mut T, b: &T) {
     *a = b.clone();
 }
 
+#[clippy::msrv = "1.62"]
+fn msrv_1_62(mut a: String, b: String, c: &str) {
+    a = b.clone();
+    // Should not be linted, as clone_into wasn't stabilized until 1.63
+    a = c.to_owned();
+}
+
+#[clippy::msrv = "1.63"]
+fn msrv_1_63(mut a: String, b: String, c: &str) {
+    a = b.clone();
+    a = c.to_owned();
+}
+
 macro_rules! clone_inside {
     ($a:expr, $b: expr) => {
         $a = $b.clone();
diff --git a/src/tools/clippy/tests/ui/assigning_clones.stderr b/src/tools/clippy/tests/ui/assigning_clones.stderr
index b76323f3606..ba59f067431 100644
--- a/src/tools/clippy/tests/ui/assigning_clones.stderr
+++ b/src/tools/clippy/tests/ui/assigning_clones.stderr
@@ -67,41 +67,59 @@ error: assigning the result of `Clone::clone()` may be inefficient
 LL |         a = b.clone();
    |         ^^^^^^^^^^^^^ help: use `clone_from()`: `a.clone_from(&b)`
 
+error: assigning the result of `Clone::clone()` may be inefficient
+  --> tests/ui/assigning_clones.rs:133:5
+   |
+LL |     a = b.clone();
+   |     ^^^^^^^^^^^^^ help: use `clone_from()`: `a.clone_from(&b)`
+
+error: assigning the result of `Clone::clone()` may be inefficient
+  --> tests/ui/assigning_clones.rs:140:5
+   |
+LL |     a = b.clone();
+   |     ^^^^^^^^^^^^^ help: use `clone_from()`: `a.clone_from(&b)`
+
+error: assigning the result of `ToOwned::to_owned()` may be inefficient
+  --> tests/ui/assigning_clones.rs:141:5
+   |
+LL |     a = c.to_owned();
+   |     ^^^^^^^^^^^^^^^^ help: use `clone_into()`: `c.clone_into(&mut a)`
+
 error: assigning the result of `ToOwned::to_owned()` may be inefficient
-  --> tests/ui/assigning_clones.rs:145:5
+  --> tests/ui/assigning_clones.rs:158:5
    |
 LL |     *mut_string = ref_str.to_owned();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_into()`: `ref_str.clone_into(mut_string)`
 
 error: assigning the result of `ToOwned::to_owned()` may be inefficient
-  --> tests/ui/assigning_clones.rs:149:5
+  --> tests/ui/assigning_clones.rs:162:5
    |
 LL |     mut_string = ref_str.to_owned();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_into()`: `ref_str.clone_into(&mut mut_string)`
 
 error: assigning the result of `ToOwned::to_owned()` may be inefficient
-  --> tests/ui/assigning_clones.rs:170:5
+  --> tests/ui/assigning_clones.rs:183:5
    |
 LL |     **mut_box_string = ref_str.to_owned();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_into()`: `ref_str.clone_into(&mut (*mut_box_string))`
 
 error: assigning the result of `ToOwned::to_owned()` may be inefficient
-  --> tests/ui/assigning_clones.rs:174:5
+  --> tests/ui/assigning_clones.rs:187:5
    |
 LL |     **mut_box_string = ref_str.to_owned();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_into()`: `ref_str.clone_into(&mut (*mut_box_string))`
 
 error: assigning the result of `ToOwned::to_owned()` may be inefficient
-  --> tests/ui/assigning_clones.rs:178:5
+  --> tests/ui/assigning_clones.rs:191:5
    |
 LL |     *mut_thing = ToOwned::to_owned(ref_str);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_into()`: `ToOwned::clone_into(ref_str, mut_thing)`
 
 error: assigning the result of `ToOwned::to_owned()` may be inefficient
-  --> tests/ui/assigning_clones.rs:182:5
+  --> tests/ui/assigning_clones.rs:195:5
    |
 LL |     mut_thing = ToOwned::to_owned(ref_str);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use `clone_into()`: `ToOwned::clone_into(ref_str, &mut mut_thing)`
 
-error: aborting due to 17 previous errors
+error: aborting due to 20 previous errors
 
diff --git a/src/tools/clippy/tests/ui/auxiliary/proc_macro_attr.rs b/src/tools/clippy/tests/ui/auxiliary/proc_macro_attr.rs
index 75f7a20f961..a6f3b164c9b 100644
--- a/src/tools/clippy/tests/ui/auxiliary/proc_macro_attr.rs
+++ b/src/tools/clippy/tests/ui/auxiliary/proc_macro_attr.rs
@@ -11,8 +11,8 @@ use quote::{quote, quote_spanned};
 use syn::spanned::Spanned;
 use syn::token::Star;
 use syn::{
-    parse_macro_input, parse_quote, FnArg, ImplItem, ItemFn, ItemImpl, ItemTrait, Lifetime, Pat, PatIdent, PatType,
-    Signature, TraitItem, Type,
+    parse_macro_input, parse_quote, FnArg, ImplItem, ItemFn, ItemImpl, ItemStruct, ItemTrait, Lifetime, Pat, PatIdent,
+    PatType, Signature, TraitItem, Type, Visibility,
 };
 
 #[proc_macro_attribute]
@@ -101,9 +101,7 @@ pub fn fake_main(_attr: TokenStream, item: TokenStream) -> TokenStream {
     let mut item = parse_macro_input!(item as ItemFn);
     let span = item.block.brace_token.span;
 
-    if item.sig.asyncness.is_some() {
-        item.sig.asyncness = None;
-    }
+    item.sig.asyncness = None;
 
     let crate_name = quote! { fake_crate };
     let block = item.block;
@@ -128,7 +126,7 @@ pub fn fake_main(_attr: TokenStream, item: TokenStream) -> TokenStream {
 
 #[proc_macro_attribute]
 pub fn fake_desugar_await(_args: TokenStream, input: TokenStream) -> TokenStream {
-    let mut async_fn = syn::parse_macro_input!(input as syn::ItemFn);
+    let mut async_fn = parse_macro_input!(input as syn::ItemFn);
 
     for stmt in &mut async_fn.block.stmts {
         if let syn::Stmt::Expr(syn::Expr::Match(syn::ExprMatch { expr: scrutinee, .. }), _) = stmt {
@@ -145,3 +143,36 @@ pub fn fake_desugar_await(_args: TokenStream, input: TokenStream) -> TokenStream
 
     quote!(#async_fn).into()
 }
+
+#[proc_macro_attribute]
+pub fn rewrite_struct(_args: TokenStream, input: TokenStream) -> TokenStream {
+    let mut item_struct = parse_macro_input!(input as syn::ItemStruct);
+    // remove struct attributes including doc comments.
+    item_struct.attrs = vec![];
+    if let Visibility::Public(token) = item_struct.vis {
+        // set vis to `pub(crate)` to trigger `missing_docs_in_private_items` lint.
+        let new_vis: Visibility = syn::parse_quote_spanned!(token.span() => pub(crate));
+        item_struct.vis = new_vis;
+    }
+    if let syn::Fields::Named(fields) = &mut item_struct.fields {
+        for field in &mut fields.named {
+            // remove all attributes from fields as well.
+            field.attrs = vec![];
+        }
+    }
+
+    quote!(#item_struct).into()
+}
+
+#[proc_macro_attribute]
+pub fn with_empty_docs(_attr: TokenStream, input: TokenStream) -> TokenStream {
+    let item = parse_macro_input!(input as syn::Item);
+    let attrs: Vec<syn::Attribute> = vec![];
+    let doc_comment = "";
+    quote! {
+        #(#attrs)*
+        #[doc = #doc_comment]
+        #item
+    }
+    .into()
+}
diff --git a/src/tools/clippy/tests/ui/await_holding_lock.rs b/src/tools/clippy/tests/ui/await_holding_lock.rs
index 27b57b64813..8e5510e6cd0 100644
--- a/src/tools/clippy/tests/ui/await_holding_lock.rs
+++ b/src/tools/clippy/tests/ui/await_holding_lock.rs
@@ -1,4 +1,5 @@
 #![warn(clippy::await_holding_lock)]
+#![allow(clippy::readonly_write_lock)]
 
 // When adding or modifying a test, please do the same for parking_lot::Mutex.
 mod std_mutex {
diff --git a/src/tools/clippy/tests/ui/await_holding_lock.stderr b/src/tools/clippy/tests/ui/await_holding_lock.stderr
index e58436345b5..0af48a36acc 100644
--- a/src/tools/clippy/tests/ui/await_holding_lock.stderr
+++ b/src/tools/clippy/tests/ui/await_holding_lock.stderr
@@ -1,12 +1,12 @@
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:9:13
+  --> tests/ui/await_holding_lock.rs:10:13
    |
 LL |         let guard = x.lock().unwrap();
    |             ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:11:15
+  --> tests/ui/await_holding_lock.rs:12:15
    |
 LL |         baz().await
    |               ^^^^^
@@ -14,40 +14,40 @@ LL |         baz().await
    = help: to override `-D warnings` add `#[allow(clippy::await_holding_lock)]`
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:25:13
+  --> tests/ui/await_holding_lock.rs:26:13
    |
 LL |         let guard = x.read().unwrap();
    |             ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:27:15
+  --> tests/ui/await_holding_lock.rs:28:15
    |
 LL |         baz().await
    |               ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:31:13
+  --> tests/ui/await_holding_lock.rs:32:13
    |
 LL |         let mut guard = x.write().unwrap();
    |             ^^^^^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:33:15
+  --> tests/ui/await_holding_lock.rs:34:15
    |
 LL |         baz().await
    |               ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:53:13
+  --> tests/ui/await_holding_lock.rs:54:13
    |
 LL |         let guard = x.lock().unwrap();
    |             ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:56:28
+  --> tests/ui/await_holding_lock.rs:57:28
    |
 LL |         let second = baz().await;
    |                            ^^^^^
@@ -56,79 +56,79 @@ LL |         let third = baz().await;
    |                           ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:67:17
+  --> tests/ui/await_holding_lock.rs:68:17
    |
 LL |             let guard = x.lock().unwrap();
    |                 ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:69:19
+  --> tests/ui/await_holding_lock.rs:70:19
    |
 LL |             baz().await
    |                   ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:80:17
+  --> tests/ui/await_holding_lock.rs:81:17
    |
 LL |             let guard = x.lock().unwrap();
    |                 ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:82:19
+  --> tests/ui/await_holding_lock.rs:83:19
    |
 LL |             baz().await
    |                   ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:93:13
+  --> tests/ui/await_holding_lock.rs:94:13
    |
 LL |         let guard = x.lock();
    |             ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:95:15
+  --> tests/ui/await_holding_lock.rs:96:15
    |
 LL |         baz().await
    |               ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:109:13
+  --> tests/ui/await_holding_lock.rs:110:13
    |
 LL |         let guard = x.read();
    |             ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:111:15
+  --> tests/ui/await_holding_lock.rs:112:15
    |
 LL |         baz().await
    |               ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:115:13
+  --> tests/ui/await_holding_lock.rs:116:13
    |
 LL |         let mut guard = x.write();
    |             ^^^^^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:117:15
+  --> tests/ui/await_holding_lock.rs:118:15
    |
 LL |         baz().await
    |               ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:137:13
+  --> tests/ui/await_holding_lock.rs:138:13
    |
 LL |         let guard = x.lock();
    |             ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:140:28
+  --> tests/ui/await_holding_lock.rs:141:28
    |
 LL |         let second = baz().await;
    |                            ^^^^^
@@ -137,40 +137,40 @@ LL |         let third = baz().await;
    |                           ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:151:17
+  --> tests/ui/await_holding_lock.rs:152:17
    |
 LL |             let guard = x.lock();
    |                 ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:153:19
+  --> tests/ui/await_holding_lock.rs:154:19
    |
 LL |             baz().await
    |                   ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:164:17
+  --> tests/ui/await_holding_lock.rs:165:17
    |
 LL |             let guard = x.lock();
    |                 ^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:166:19
+  --> tests/ui/await_holding_lock.rs:167:19
    |
 LL |             baz().await
    |                   ^^^^^
 
 error: this `MutexGuard` is held across an `await` point
-  --> tests/ui/await_holding_lock.rs:185:9
+  --> tests/ui/await_holding_lock.rs:186:9
    |
 LL |     let mut guard = x.lock().unwrap();
    |         ^^^^^^^^^
    |
    = help: consider using an async-aware `Mutex` type or ensuring the `MutexGuard` is dropped before calling await
 note: these are all the `await` points this lock is held through
-  --> tests/ui/await_holding_lock.rs:189:11
+  --> tests/ui/await_holding_lock.rs:190:11
    |
 LL |     baz().await;
    |           ^^^^^
diff --git a/src/tools/clippy/tests/ui/bool_assert_comparison.fixed b/src/tools/clippy/tests/ui/bool_assert_comparison.fixed
index 63b8e27e1c6..b05166a055e 100644
--- a/src/tools/clippy/tests/ui/bool_assert_comparison.fixed
+++ b/src/tools/clippy/tests/ui/bool_assert_comparison.fixed
@@ -1,4 +1,4 @@
-#![allow(unused, clippy::assertions_on_constants)]
+#![allow(unused, clippy::assertions_on_constants, clippy::const_is_empty)]
 #![warn(clippy::bool_assert_comparison)]
 
 use std::ops::Not;
diff --git a/src/tools/clippy/tests/ui/bool_assert_comparison.rs b/src/tools/clippy/tests/ui/bool_assert_comparison.rs
index 58f81fedb79..dc51fcf1d36 100644
--- a/src/tools/clippy/tests/ui/bool_assert_comparison.rs
+++ b/src/tools/clippy/tests/ui/bool_assert_comparison.rs
@@ -1,4 +1,4 @@
-#![allow(unused, clippy::assertions_on_constants)]
+#![allow(unused, clippy::assertions_on_constants, clippy::const_is_empty)]
 #![warn(clippy::bool_assert_comparison)]
 
 use std::ops::Not;
diff --git a/src/tools/clippy/tests/ui/cast_lossless_bool.fixed b/src/tools/clippy/tests/ui/cast_lossless_bool.fixed
index a4ce1c6f928..51a38a60cf6 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_bool.fixed
+++ b/src/tools/clippy/tests/ui/cast_lossless_bool.fixed
@@ -1,6 +1,8 @@
 #![allow(dead_code)]
 #![warn(clippy::cast_lossless)]
 
+type U8 = u8;
+
 fn main() {
     // Test clippy::cast_lossless with casts to integer types
     let _ = u8::from(true);
@@ -19,6 +21,8 @@ fn main() {
 
     // Test with an expression wrapped in parens
     let _ = u16::from(true | false);
+
+    let _ = U8::from(true);
 }
 
 // The lint would suggest using `u32::from(input)` here but the `XX::from` function is not const,
diff --git a/src/tools/clippy/tests/ui/cast_lossless_bool.rs b/src/tools/clippy/tests/ui/cast_lossless_bool.rs
index e5b1c30c103..cb307bd68e4 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_bool.rs
+++ b/src/tools/clippy/tests/ui/cast_lossless_bool.rs
@@ -1,6 +1,8 @@
 #![allow(dead_code)]
 #![warn(clippy::cast_lossless)]
 
+type U8 = u8;
+
 fn main() {
     // Test clippy::cast_lossless with casts to integer types
     let _ = true as u8;
@@ -19,6 +21,8 @@ fn main() {
 
     // Test with an expression wrapped in parens
     let _ = (true | false) as u16;
+
+    let _ = true as U8;
 }
 
 // The lint would suggest using `u32::from(input)` here but the `XX::from` function is not const,
diff --git a/src/tools/clippy/tests/ui/cast_lossless_bool.stderr b/src/tools/clippy/tests/ui/cast_lossless_bool.stderr
index 792b30b7a38..b47b35461f6 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_bool.stderr
+++ b/src/tools/clippy/tests/ui/cast_lossless_bool.stderr
@@ -1,5 +1,5 @@
 error: casting `bool` to `u8` is more cleanly stated with `u8::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:6:13
+  --> tests/ui/cast_lossless_bool.rs:8:13
    |
 LL |     let _ = true as u8;
    |             ^^^^^^^^^^ help: try: `u8::from(true)`
@@ -8,82 +8,88 @@ LL |     let _ = true as u8;
    = help: to override `-D warnings` add `#[allow(clippy::cast_lossless)]`
 
 error: casting `bool` to `u16` is more cleanly stated with `u16::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:7:13
+  --> tests/ui/cast_lossless_bool.rs:9:13
    |
 LL |     let _ = true as u16;
    |             ^^^^^^^^^^^ help: try: `u16::from(true)`
 
 error: casting `bool` to `u32` is more cleanly stated with `u32::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:8:13
+  --> tests/ui/cast_lossless_bool.rs:10:13
    |
 LL |     let _ = true as u32;
    |             ^^^^^^^^^^^ help: try: `u32::from(true)`
 
 error: casting `bool` to `u64` is more cleanly stated with `u64::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:9:13
+  --> tests/ui/cast_lossless_bool.rs:11:13
    |
 LL |     let _ = true as u64;
    |             ^^^^^^^^^^^ help: try: `u64::from(true)`
 
 error: casting `bool` to `u128` is more cleanly stated with `u128::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:10:13
+  --> tests/ui/cast_lossless_bool.rs:12:13
    |
 LL |     let _ = true as u128;
    |             ^^^^^^^^^^^^ help: try: `u128::from(true)`
 
 error: casting `bool` to `usize` is more cleanly stated with `usize::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:11:13
+  --> tests/ui/cast_lossless_bool.rs:13:13
    |
 LL |     let _ = true as usize;
    |             ^^^^^^^^^^^^^ help: try: `usize::from(true)`
 
 error: casting `bool` to `i8` is more cleanly stated with `i8::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:13:13
+  --> tests/ui/cast_lossless_bool.rs:15:13
    |
 LL |     let _ = true as i8;
    |             ^^^^^^^^^^ help: try: `i8::from(true)`
 
 error: casting `bool` to `i16` is more cleanly stated with `i16::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:14:13
+  --> tests/ui/cast_lossless_bool.rs:16:13
    |
 LL |     let _ = true as i16;
    |             ^^^^^^^^^^^ help: try: `i16::from(true)`
 
 error: casting `bool` to `i32` is more cleanly stated with `i32::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:15:13
+  --> tests/ui/cast_lossless_bool.rs:17:13
    |
 LL |     let _ = true as i32;
    |             ^^^^^^^^^^^ help: try: `i32::from(true)`
 
 error: casting `bool` to `i64` is more cleanly stated with `i64::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:16:13
+  --> tests/ui/cast_lossless_bool.rs:18:13
    |
 LL |     let _ = true as i64;
    |             ^^^^^^^^^^^ help: try: `i64::from(true)`
 
 error: casting `bool` to `i128` is more cleanly stated with `i128::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:17:13
+  --> tests/ui/cast_lossless_bool.rs:19:13
    |
 LL |     let _ = true as i128;
    |             ^^^^^^^^^^^^ help: try: `i128::from(true)`
 
 error: casting `bool` to `isize` is more cleanly stated with `isize::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:18:13
+  --> tests/ui/cast_lossless_bool.rs:20:13
    |
 LL |     let _ = true as isize;
    |             ^^^^^^^^^^^^^ help: try: `isize::from(true)`
 
 error: casting `bool` to `u16` is more cleanly stated with `u16::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:21:13
+  --> tests/ui/cast_lossless_bool.rs:23:13
    |
 LL |     let _ = (true | false) as u16;
    |             ^^^^^^^^^^^^^^^^^^^^^ help: try: `u16::from(true | false)`
 
+error: casting `bool` to `U8` is more cleanly stated with `U8::from(_)`
+  --> tests/ui/cast_lossless_bool.rs:25:13
+   |
+LL |     let _ = true as U8;
+   |             ^^^^^^^^^^ help: try: `U8::from(true)`
+
 error: casting `bool` to `u8` is more cleanly stated with `u8::from(_)`
-  --> tests/ui/cast_lossless_bool.rs:49:13
+  --> tests/ui/cast_lossless_bool.rs:53:13
    |
 LL |     let _ = true as u8;
    |             ^^^^^^^^^^ help: try: `u8::from(true)`
 
-error: aborting due to 14 previous errors
+error: aborting due to 15 previous errors
 
diff --git a/src/tools/clippy/tests/ui/cast_lossless_float.fixed b/src/tools/clippy/tests/ui/cast_lossless_float.fixed
index f4f2e4773a5..96a67b1945c 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_float.fixed
+++ b/src/tools/clippy/tests/ui/cast_lossless_float.fixed
@@ -1,11 +1,16 @@
 #![allow(clippy::no_effect, clippy::unnecessary_operation, dead_code)]
 #![warn(clippy::cast_lossless)]
 
+type F32 = f32;
+type F64 = f64;
+
 fn main() {
     // Test clippy::cast_lossless with casts to floating-point types
     let x0 = 1i8;
     let _ = f32::from(x0);
     let _ = f64::from(x0);
+    let _ = F32::from(x0);
+    let _ = F64::from(x0);
     let x1 = 1u8;
     let _ = f32::from(x1);
     let _ = f64::from(x1);
diff --git a/src/tools/clippy/tests/ui/cast_lossless_float.rs b/src/tools/clippy/tests/ui/cast_lossless_float.rs
index fdd88ed36fc..d37b2c1d920 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_float.rs
+++ b/src/tools/clippy/tests/ui/cast_lossless_float.rs
@@ -1,11 +1,16 @@
 #![allow(clippy::no_effect, clippy::unnecessary_operation, dead_code)]
 #![warn(clippy::cast_lossless)]
 
+type F32 = f32;
+type F64 = f64;
+
 fn main() {
     // Test clippy::cast_lossless with casts to floating-point types
     let x0 = 1i8;
     let _ = x0 as f32;
     let _ = x0 as f64;
+    let _ = x0 as F32;
+    let _ = x0 as F64;
     let x1 = 1u8;
     let _ = x1 as f32;
     let _ = x1 as f64;
diff --git a/src/tools/clippy/tests/ui/cast_lossless_float.stderr b/src/tools/clippy/tests/ui/cast_lossless_float.stderr
index e70f81eb91f..ad7de760adf 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_float.stderr
+++ b/src/tools/clippy/tests/ui/cast_lossless_float.stderr
@@ -1,5 +1,5 @@
 error: casting `i8` to `f32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:7:13
+  --> tests/ui/cast_lossless_float.rs:10:13
    |
 LL |     let _ = x0 as f32;
    |             ^^^^^^^^^ help: try: `f32::from(x0)`
@@ -8,64 +8,76 @@ LL |     let _ = x0 as f32;
    = help: to override `-D warnings` add `#[allow(clippy::cast_lossless)]`
 
 error: casting `i8` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:8:13
+  --> tests/ui/cast_lossless_float.rs:11:13
    |
 LL |     let _ = x0 as f64;
    |             ^^^^^^^^^ help: try: `f64::from(x0)`
 
+error: casting `i8` to `F32` may become silently lossy if you later change the type
+  --> tests/ui/cast_lossless_float.rs:12:13
+   |
+LL |     let _ = x0 as F32;
+   |             ^^^^^^^^^ help: try: `F32::from(x0)`
+
+error: casting `i8` to `F64` may become silently lossy if you later change the type
+  --> tests/ui/cast_lossless_float.rs:13:13
+   |
+LL |     let _ = x0 as F64;
+   |             ^^^^^^^^^ help: try: `F64::from(x0)`
+
 error: casting `u8` to `f32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:10:13
+  --> tests/ui/cast_lossless_float.rs:15:13
    |
 LL |     let _ = x1 as f32;
    |             ^^^^^^^^^ help: try: `f32::from(x1)`
 
 error: casting `u8` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:11:13
+  --> tests/ui/cast_lossless_float.rs:16:13
    |
 LL |     let _ = x1 as f64;
    |             ^^^^^^^^^ help: try: `f64::from(x1)`
 
 error: casting `i16` to `f32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:13:13
+  --> tests/ui/cast_lossless_float.rs:18:13
    |
 LL |     let _ = x2 as f32;
    |             ^^^^^^^^^ help: try: `f32::from(x2)`
 
 error: casting `i16` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:14:13
+  --> tests/ui/cast_lossless_float.rs:19:13
    |
 LL |     let _ = x2 as f64;
    |             ^^^^^^^^^ help: try: `f64::from(x2)`
 
 error: casting `u16` to `f32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:16:13
+  --> tests/ui/cast_lossless_float.rs:21:13
    |
 LL |     let _ = x3 as f32;
    |             ^^^^^^^^^ help: try: `f32::from(x3)`
 
 error: casting `u16` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:17:13
+  --> tests/ui/cast_lossless_float.rs:22:13
    |
 LL |     let _ = x3 as f64;
    |             ^^^^^^^^^ help: try: `f64::from(x3)`
 
 error: casting `i32` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:19:13
+  --> tests/ui/cast_lossless_float.rs:24:13
    |
 LL |     let _ = x4 as f64;
    |             ^^^^^^^^^ help: try: `f64::from(x4)`
 
 error: casting `u32` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:21:13
+  --> tests/ui/cast_lossless_float.rs:26:13
    |
 LL |     let _ = x5 as f64;
    |             ^^^^^^^^^ help: try: `f64::from(x5)`
 
 error: casting `f32` to `f64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_float.rs:24:13
+  --> tests/ui/cast_lossless_float.rs:29:13
    |
 LL |     let _ = 1.0f32 as f64;
    |             ^^^^^^^^^^^^^ help: try: `f64::from(1.0f32)`
 
-error: aborting due to 11 previous errors
+error: aborting due to 13 previous errors
 
diff --git a/src/tools/clippy/tests/ui/cast_lossless_integer.fixed b/src/tools/clippy/tests/ui/cast_lossless_integer.fixed
index 5e7e545e764..291556a9774 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_integer.fixed
+++ b/src/tools/clippy/tests/ui/cast_lossless_integer.fixed
@@ -1,6 +1,9 @@
 #![allow(clippy::no_effect, clippy::unnecessary_operation, dead_code)]
 #![warn(clippy::cast_lossless)]
 
+type I64 = i64;
+type U128 = u128;
+
 fn main() {
     // Test clippy::cast_lossless with casts to integer types
     let _ = i16::from(1i8);
@@ -24,6 +27,13 @@ fn main() {
 
     // Test with an expression wrapped in parens
     let _ = u16::from(1u8 + 1u8);
+
+    let _ = I64::from(1i8);
+
+    // Do not lint if destination type is u128
+    // see https://github.com/rust-lang/rust-clippy/issues/12492
+    let _ = 1u8 as u128;
+    let _ = 1u8 as U128;
 }
 
 // The lint would suggest using `f64::from(input)` here but the `XX::from` function is not const,
diff --git a/src/tools/clippy/tests/ui/cast_lossless_integer.rs b/src/tools/clippy/tests/ui/cast_lossless_integer.rs
index 0d69ddbd586..a917c7a371d 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_integer.rs
+++ b/src/tools/clippy/tests/ui/cast_lossless_integer.rs
@@ -1,6 +1,9 @@
 #![allow(clippy::no_effect, clippy::unnecessary_operation, dead_code)]
 #![warn(clippy::cast_lossless)]
 
+type I64 = i64;
+type U128 = u128;
+
 fn main() {
     // Test clippy::cast_lossless with casts to integer types
     let _ = 1i8 as i16;
@@ -24,6 +27,13 @@ fn main() {
 
     // Test with an expression wrapped in parens
     let _ = (1u8 + 1u8) as u16;
+
+    let _ = 1i8 as I64;
+
+    // Do not lint if destination type is u128
+    // see https://github.com/rust-lang/rust-clippy/issues/12492
+    let _ = 1u8 as u128;
+    let _ = 1u8 as U128;
 }
 
 // The lint would suggest using `f64::from(input)` here but the `XX::from` function is not const,
diff --git a/src/tools/clippy/tests/ui/cast_lossless_integer.stderr b/src/tools/clippy/tests/ui/cast_lossless_integer.stderr
index 43d4ce3ce91..aaece939285 100644
--- a/src/tools/clippy/tests/ui/cast_lossless_integer.stderr
+++ b/src/tools/clippy/tests/ui/cast_lossless_integer.stderr
@@ -1,5 +1,5 @@
 error: casting `i8` to `i16` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:6:13
+  --> tests/ui/cast_lossless_integer.rs:9:13
    |
 LL |     let _ = 1i8 as i16;
    |             ^^^^^^^^^^ help: try: `i16::from(1i8)`
@@ -8,124 +8,130 @@ LL |     let _ = 1i8 as i16;
    = help: to override `-D warnings` add `#[allow(clippy::cast_lossless)]`
 
 error: casting `i8` to `i32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:7:13
+  --> tests/ui/cast_lossless_integer.rs:10:13
    |
 LL |     let _ = 1i8 as i32;
    |             ^^^^^^^^^^ help: try: `i32::from(1i8)`
 
 error: casting `i8` to `i64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:8:13
+  --> tests/ui/cast_lossless_integer.rs:11:13
    |
 LL |     let _ = 1i8 as i64;
    |             ^^^^^^^^^^ help: try: `i64::from(1i8)`
 
 error: casting `u8` to `i16` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:9:13
+  --> tests/ui/cast_lossless_integer.rs:12:13
    |
 LL |     let _ = 1u8 as i16;
    |             ^^^^^^^^^^ help: try: `i16::from(1u8)`
 
 error: casting `u8` to `i32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:10:13
+  --> tests/ui/cast_lossless_integer.rs:13:13
    |
 LL |     let _ = 1u8 as i32;
    |             ^^^^^^^^^^ help: try: `i32::from(1u8)`
 
 error: casting `u8` to `i64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:11:13
+  --> tests/ui/cast_lossless_integer.rs:14:13
    |
 LL |     let _ = 1u8 as i64;
    |             ^^^^^^^^^^ help: try: `i64::from(1u8)`
 
 error: casting `u8` to `u16` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:12:13
+  --> tests/ui/cast_lossless_integer.rs:15:13
    |
 LL |     let _ = 1u8 as u16;
    |             ^^^^^^^^^^ help: try: `u16::from(1u8)`
 
 error: casting `u8` to `u32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:13:13
+  --> tests/ui/cast_lossless_integer.rs:16:13
    |
 LL |     let _ = 1u8 as u32;
    |             ^^^^^^^^^^ help: try: `u32::from(1u8)`
 
 error: casting `u8` to `u64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:14:13
+  --> tests/ui/cast_lossless_integer.rs:17:13
    |
 LL |     let _ = 1u8 as u64;
    |             ^^^^^^^^^^ help: try: `u64::from(1u8)`
 
 error: casting `i16` to `i32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:15:13
+  --> tests/ui/cast_lossless_integer.rs:18:13
    |
 LL |     let _ = 1i16 as i32;
    |             ^^^^^^^^^^^ help: try: `i32::from(1i16)`
 
 error: casting `i16` to `i64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:16:13
+  --> tests/ui/cast_lossless_integer.rs:19:13
    |
 LL |     let _ = 1i16 as i64;
    |             ^^^^^^^^^^^ help: try: `i64::from(1i16)`
 
 error: casting `u16` to `i32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:17:13
+  --> tests/ui/cast_lossless_integer.rs:20:13
    |
 LL |     let _ = 1u16 as i32;
    |             ^^^^^^^^^^^ help: try: `i32::from(1u16)`
 
 error: casting `u16` to `i64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:18:13
+  --> tests/ui/cast_lossless_integer.rs:21:13
    |
 LL |     let _ = 1u16 as i64;
    |             ^^^^^^^^^^^ help: try: `i64::from(1u16)`
 
 error: casting `u16` to `u32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:19:13
+  --> tests/ui/cast_lossless_integer.rs:22:13
    |
 LL |     let _ = 1u16 as u32;
    |             ^^^^^^^^^^^ help: try: `u32::from(1u16)`
 
 error: casting `u16` to `u64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:20:13
+  --> tests/ui/cast_lossless_integer.rs:23:13
    |
 LL |     let _ = 1u16 as u64;
    |             ^^^^^^^^^^^ help: try: `u64::from(1u16)`
 
 error: casting `i32` to `i64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:21:13
+  --> tests/ui/cast_lossless_integer.rs:24:13
    |
 LL |     let _ = 1i32 as i64;
    |             ^^^^^^^^^^^ help: try: `i64::from(1i32)`
 
 error: casting `u32` to `i64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:22:13
+  --> tests/ui/cast_lossless_integer.rs:25:13
    |
 LL |     let _ = 1u32 as i64;
    |             ^^^^^^^^^^^ help: try: `i64::from(1u32)`
 
 error: casting `u32` to `u64` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:23:13
+  --> tests/ui/cast_lossless_integer.rs:26:13
    |
 LL |     let _ = 1u32 as u64;
    |             ^^^^^^^^^^^ help: try: `u64::from(1u32)`
 
 error: casting `u8` to `u16` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:26:13
+  --> tests/ui/cast_lossless_integer.rs:29:13
    |
 LL |     let _ = (1u8 + 1u8) as u16;
    |             ^^^^^^^^^^^^^^^^^^ help: try: `u16::from(1u8 + 1u8)`
 
+error: casting `i8` to `I64` may become silently lossy if you later change the type
+  --> tests/ui/cast_lossless_integer.rs:31:13
+   |
+LL |     let _ = 1i8 as I64;
+   |             ^^^^^^^^^^ help: try: `I64::from(1i8)`
+
 error: casting `i8` to `i32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:60:13
+  --> tests/ui/cast_lossless_integer.rs:70:13
    |
 LL |     let _ = sign_cast!(x, u8, i8) as i32;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `i32::from(sign_cast!(x, u8, i8))`
 
 error: casting `i8` to `i32` may become silently lossy if you later change the type
-  --> tests/ui/cast_lossless_integer.rs:61:13
+  --> tests/ui/cast_lossless_integer.rs:71:13
    |
 LL |     let _ = (sign_cast!(x, u8, i8) + 1) as i32;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `i32::from(sign_cast!(x, u8, i8) + 1)`
 
-error: aborting due to 21 previous errors
+error: aborting due to 22 previous errors
 
diff --git a/src/tools/clippy/tests/ui/const_is_empty.rs b/src/tools/clippy/tests/ui/const_is_empty.rs
new file mode 100644
index 00000000000..ae37a82e4f9
--- /dev/null
+++ b/src/tools/clippy/tests/ui/const_is_empty.rs
@@ -0,0 +1,174 @@
+#![feature(inline_const)]
+#![warn(clippy::const_is_empty)]
+#![allow(clippy::needless_late_init, unused_must_use)]
+
+fn test_literal() {
+    if "".is_empty() {
+        //~^ERROR: this expression always evaluates to true
+    }
+    if "foobar".is_empty() {
+        //~^ERROR: this expression always evaluates to false
+    }
+}
+
+fn test_byte_literal() {
+    if b"".is_empty() {
+        //~^ERROR: this expression always evaluates to true
+    }
+    if b"foobar".is_empty() {
+        //~^ERROR: this expression always evaluates to false
+    }
+}
+
+fn test_no_mut() {
+    let mut empty = "";
+    if empty.is_empty() {
+        // No lint because it is mutable
+    }
+}
+
+fn test_propagated() {
+    let empty = "";
+    let non_empty = "foobar";
+    let empty2 = empty;
+    let non_empty2 = non_empty;
+    if empty2.is_empty() {
+        //~^ERROR: this expression always evaluates to true
+    }
+    if non_empty2.is_empty() {
+        //~^ERROR: this expression always evaluates to false
+    }
+}
+
+const EMPTY_STR: &str = "";
+const NON_EMPTY_STR: &str = "foo";
+const EMPTY_BSTR: &[u8] = b"";
+const NON_EMPTY_BSTR: &[u8] = b"foo";
+const EMPTY_U8_SLICE: &[u8] = &[];
+const NON_EMPTY_U8_SLICE: &[u8] = &[1, 2];
+const EMPTY_SLICE: &[u32] = &[];
+const NON_EMPTY_SLICE: &[u32] = &[1, 2];
+const NON_EMPTY_SLICE_REPEAT: &[u32] = &[1; 2];
+const EMPTY_ARRAY: [u32; 0] = [];
+const EMPTY_ARRAY_REPEAT: [u32; 0] = [1; 0];
+const NON_EMPTY_ARRAY: [u32; 2] = [1, 2];
+const NON_EMPTY_ARRAY_REPEAT: [u32; 2] = [1; 2];
+const EMPTY_REF_ARRAY: &[u32; 0] = &[];
+const NON_EMPTY_REF_ARRAY: &[u32; 3] = &[1, 2, 3];
+
+fn test_from_const() {
+    let _ = EMPTY_STR.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = NON_EMPTY_STR.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = EMPTY_BSTR.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = NON_EMPTY_BSTR.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = EMPTY_ARRAY.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = EMPTY_ARRAY_REPEAT.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = EMPTY_U8_SLICE.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = NON_EMPTY_U8_SLICE.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = NON_EMPTY_ARRAY.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = NON_EMPTY_ARRAY_REPEAT.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = EMPTY_REF_ARRAY.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = NON_EMPTY_REF_ARRAY.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = EMPTY_SLICE.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = NON_EMPTY_SLICE.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = NON_EMPTY_SLICE_REPEAT.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+}
+
+fn main() {
+    let value = "foobar";
+    let _ = value.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let x = value;
+    let _ = x.is_empty();
+    //~^ ERROR: this expression always evaluates to false
+    let _ = "".is_empty();
+    //~^ ERROR: this expression always evaluates to true
+    let _ = b"".is_empty();
+    //~^ ERROR: this expression always evaluates to true
+}
+
+fn str_from_arg(var: &str) {
+    var.is_empty();
+    // Do not lint, we know nothiny about var
+}
+
+fn update_str() {
+    let mut value = "duck";
+    value = "penguin";
+
+    let _ = value.is_empty();
+    // Do not lint since value is mutable
+}
+
+fn macros() {
+    // Content from Macro
+    let file = include_str!("const_is_empty.rs");
+    let _ = file.is_empty();
+    // No lint because initializer comes from a macro result
+
+    let var = env!("PATH");
+    let _ = var.is_empty();
+    // No lint because initializer comes from a macro result
+}
+
+fn conditional_value() {
+    let value;
+
+    if true {
+        value = "hey";
+    } else {
+        value = "hej";
+    }
+
+    let _ = value.is_empty();
+    // Do not lint, current constant folding is too simple to detect this
+}
+
+fn cfg_conditioned() {
+    #[cfg(test)]
+    let val = "";
+    #[cfg(not(test))]
+    let val = "foo";
+
+    let _ = val.is_empty();
+    // Do not lint, value depend on a #[cfg(…)] directive
+}
+
+fn not_cfg_conditioned() {
+    let val = "";
+    #[cfg(not(target_os = "inexistent"))]
+    let _ = val.is_empty();
+    //~^ ERROR: this expression always evaluates to true
+}
+
+const fn const_rand() -> &'static str {
+    "17"
+}
+
+fn const_expressions() {
+    let _ = const { if true { "1" } else { "2" } }.is_empty();
+    // Do not lint, we do not recurse into boolean expressions
+
+    let _ = const_rand().is_empty();
+    // Do not lint, we do not recurse into functions
+}
+
+fn constant_from_external_crate() {
+    let _ = std::env::consts::EXE_EXTENSION.is_empty();
+    // Do not lint, `exe_ext` comes from the `std` crate
+}
diff --git a/src/tools/clippy/tests/ui/const_is_empty.stderr b/src/tools/clippy/tests/ui/const_is_empty.stderr
new file mode 100644
index 00000000000..0e09da77bb4
--- /dev/null
+++ b/src/tools/clippy/tests/ui/const_is_empty.stderr
@@ -0,0 +1,161 @@
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:6:8
+   |
+LL |     if "".is_empty() {
+   |        ^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::const-is-empty` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::const_is_empty)]`
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:9:8
+   |
+LL |     if "foobar".is_empty() {
+   |        ^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:15:8
+   |
+LL |     if b"".is_empty() {
+   |        ^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:18:8
+   |
+LL |     if b"foobar".is_empty() {
+   |        ^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:35:8
+   |
+LL |     if empty2.is_empty() {
+   |        ^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:38:8
+   |
+LL |     if non_empty2.is_empty() {
+   |        ^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:60:13
+   |
+LL |     let _ = EMPTY_STR.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:62:13
+   |
+LL |     let _ = NON_EMPTY_STR.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:64:13
+   |
+LL |     let _ = EMPTY_BSTR.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:66:13
+   |
+LL |     let _ = NON_EMPTY_BSTR.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:68:13
+   |
+LL |     let _ = EMPTY_ARRAY.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:70:13
+   |
+LL |     let _ = EMPTY_ARRAY_REPEAT.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:72:13
+   |
+LL |     let _ = EMPTY_U8_SLICE.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:74:13
+   |
+LL |     let _ = NON_EMPTY_U8_SLICE.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:76:13
+   |
+LL |     let _ = NON_EMPTY_ARRAY.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:78:13
+   |
+LL |     let _ = NON_EMPTY_ARRAY_REPEAT.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:80:13
+   |
+LL |     let _ = EMPTY_REF_ARRAY.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:82:13
+   |
+LL |     let _ = NON_EMPTY_REF_ARRAY.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:84:13
+   |
+LL |     let _ = EMPTY_SLICE.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:86:13
+   |
+LL |     let _ = NON_EMPTY_SLICE.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:88:13
+   |
+LL |     let _ = NON_EMPTY_SLICE_REPEAT.is_empty();
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:94:13
+   |
+LL |     let _ = value.is_empty();
+   |             ^^^^^^^^^^^^^^^^
+
+error: this expression always evaluates to false
+  --> tests/ui/const_is_empty.rs:97:13
+   |
+LL |     let _ = x.is_empty();
+   |             ^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:99:13
+   |
+LL |     let _ = "".is_empty();
+   |             ^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:101:13
+   |
+LL |     let _ = b"".is_empty();
+   |             ^^^^^^^^^^^^^^
+
+error: this expression always evaluates to true
+  --> tests/ui/const_is_empty.rs:155:13
+   |
+LL |     let _ = val.is_empty();
+   |             ^^^^^^^^^^^^^^
+
+error: aborting due to 26 previous errors
+
diff --git a/src/tools/clippy/tests/ui/crashes/ice-12491.fixed b/src/tools/clippy/tests/ui/crashes/ice-12491.fixed
new file mode 100644
index 00000000000..4ea480b0663
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-12491.fixed
@@ -0,0 +1,7 @@
+#![warn(clippy::needless_return)]
+
+fn main() {
+    if (true) {
+        // anything一些中文
+    }
+}
diff --git a/src/tools/clippy/tests/ui/crashes/ice-12491.rs b/src/tools/clippy/tests/ui/crashes/ice-12491.rs
new file mode 100644
index 00000000000..60add6afa2c
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-12491.rs
@@ -0,0 +1,8 @@
+#![warn(clippy::needless_return)]
+
+fn main() {
+    if (true) {
+        // anything一些中文
+        return;
+    }
+}
diff --git a/src/tools/clippy/tests/ui/crashes/ice-12491.stderr b/src/tools/clippy/tests/ui/crashes/ice-12491.stderr
new file mode 100644
index 00000000000..7cc418898e8
--- /dev/null
+++ b/src/tools/clippy/tests/ui/crashes/ice-12491.stderr
@@ -0,0 +1,19 @@
+error: unneeded `return` statement
+  --> tests/ui/crashes/ice-12491.rs:5:24
+   |
+LL |           // anything一些中文
+   |  ____________________________^
+LL | |         return;
+   | |______________^
+   |
+   = note: `-D clippy::needless-return` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::needless_return)]`
+help: remove `return`
+   |
+LL -         // anything一些中文
+LL -         return;
+LL +         // anything一些中文
+   |
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.fixed b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.fixed
new file mode 100644
index 00000000000..e3525191423
--- /dev/null
+++ b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.fixed
@@ -0,0 +1,111 @@
+#![warn(clippy::dbg_macro)]
+#![allow(clippy::unnecessary_operation, clippy::no_effect)]
+
+fn foo(n: u32) -> u32 {
+    if let Some(n) = n.checked_sub(4) { n } else { n }
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+}
+fn bar(_: ()) {}
+
+fn factorial(n: u32) -> u32 {
+    if n <= 1 {
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+        1
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    } else {
+        n * factorial(n - 1)
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    }
+}
+
+fn main() {
+    42;
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    foo(3) + factorial(4);
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    (1, 2, 3, 4, 5);
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+}
+
+fn issue9914() {
+    macro_rules! foo {
+        ($x:expr) => {
+            $x;
+        };
+    }
+    macro_rules! foo2 {
+        ($x:expr) => {
+            $x;
+        };
+    }
+    macro_rules! expand_to_dbg {
+        () => {
+            
+            //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+        };
+    }
+
+    
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    #[allow(clippy::let_unit_value)]
+    let _ = ();
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    bar(());
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    foo!(());
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    foo2!(foo!(()));
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    expand_to_dbg!();
+}
+
+mod issue7274 {
+    trait Thing<'b> {
+        fn foo(&self);
+    }
+
+    macro_rules! define_thing {
+        ($thing:ident, $body:expr) => {
+            impl<'a> Thing<'a> for $thing {
+                fn foo<'b>(&self) {
+                    $body
+                }
+            }
+        };
+    }
+
+    struct MyThing;
+    define_thing!(MyThing, {
+        2;
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    });
+}
+
+#[test]
+pub fn issue8481() {
+    1;
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+}
+
+#[cfg(test)]
+fn foo2() {
+    1;
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+}
+
+#[cfg(test)]
+mod mod1 {
+    fn func() {
+        1;
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    }
+}
+
+mod issue12131 {
+    fn dbg_in_print(s: &str) {
+        println!("dbg: {:?}", s);
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+        print!("{}", s);
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    }
+}
diff --git a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.rs b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.rs
index 3f4770c63d0..80606c2db05 100644
--- a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.rs
+++ b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.rs
@@ -1,9 +1,5 @@
-//@no-rustfix
-
 #![warn(clippy::dbg_macro)]
-
-#[path = "auxiliary/submodule.rs"]
-mod submodule;
+#![allow(clippy::unnecessary_operation, clippy::no_effect)]
 
 fn foo(n: u32) -> u32 {
     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
@@ -25,12 +21,8 @@ fn factorial(n: u32) -> u32 {
 fn main() {
     dbg!(42);
     //~^ ERROR: the `dbg!` macro is intended as a debugging tool
-    dbg!(dbg!(dbg!(42)));
-    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
     foo(3) + dbg!(factorial(4));
     //~^ ERROR: the `dbg!` macro is intended as a debugging tool
-    dbg!(1, 2, dbg!(3, 4));
-    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
     dbg!(1, 2, 3, 4, 5);
     //~^ ERROR: the `dbg!` macro is intended as a debugging tool
 }
@@ -49,6 +41,7 @@ fn issue9914() {
     macro_rules! expand_to_dbg {
         () => {
             dbg!();
+            //~^ ERROR: the `dbg!` macro is intended as a debugging tool
         };
     }
 
@@ -107,3 +100,12 @@ mod mod1 {
         //~^ ERROR: the `dbg!` macro is intended as a debugging tool
     }
 }
+
+mod issue12131 {
+    fn dbg_in_print(s: &str) {
+        println!("dbg: {:?}", dbg!(s));
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+        print!("{}", dbg!(s));
+        //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    }
+}
diff --git a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.stderr b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.stderr
index 5ad0bbfed94..86667701da0 100644
--- a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.stderr
+++ b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro.stderr
@@ -1,30 +1,18 @@
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/auxiliary/submodule.rs:2:5
-   |
-LL |     dbg!();
-   |     ^^^^^^^
-   |
-   = note: `-D clippy::dbg-macro` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(clippy::dbg_macro)]`
-help: remove the invocation before committing it to a version control system
-   |
-LL -     dbg!();
-LL +     
-   |
-
-error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:9:22
+  --> tests/ui/dbg_macro/dbg_macro.rs:5:22
    |
 LL |     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
    |                      ^^^^^^^^^^^^^^^^^^^^^^
    |
+   = note: `-D clippy::dbg-macro` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::dbg_macro)]`
 help: remove the invocation before committing it to a version control system
    |
 LL |     if let Some(n) = n.checked_sub(4) { n } else { n }
    |                      ~~~~~~~~~~~~~~~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:15:8
+  --> tests/ui/dbg_macro/dbg_macro.rs:11:8
    |
 LL |     if dbg!(n <= 1) {
    |        ^^^^^^^^^^^^
@@ -35,7 +23,7 @@ LL |     if n <= 1 {
    |        ~~~~~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:17:9
+  --> tests/ui/dbg_macro/dbg_macro.rs:13:9
    |
 LL |         dbg!(1)
    |         ^^^^^^^
@@ -46,7 +34,7 @@ LL |         1
    |
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:20:9
+  --> tests/ui/dbg_macro/dbg_macro.rs:16:9
    |
 LL |         dbg!(n * factorial(n - 1))
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -57,7 +45,7 @@ LL |         n * factorial(n - 1)
    |
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:26:5
+  --> tests/ui/dbg_macro/dbg_macro.rs:22:5
    |
 LL |     dbg!(42);
    |     ^^^^^^^^
@@ -68,18 +56,7 @@ LL |     42;
    |     ~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:28:5
-   |
-LL |     dbg!(dbg!(dbg!(42)));
-   |     ^^^^^^^^^^^^^^^^^^^^
-   |
-help: remove the invocation before committing it to a version control system
-   |
-LL |     dbg!(dbg!(42));
-   |     ~~~~~~~~~~~~~~
-
-error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:30:14
+  --> tests/ui/dbg_macro/dbg_macro.rs:24:14
    |
 LL |     foo(3) + dbg!(factorial(4));
    |              ^^^^^^^^^^^^^^^^^^
@@ -90,18 +67,7 @@ LL |     foo(3) + factorial(4);
    |              ~~~~~~~~~~~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:32:5
-   |
-LL |     dbg!(1, 2, dbg!(3, 4));
-   |     ^^^^^^^^^^^^^^^^^^^^^^
-   |
-help: remove the invocation before committing it to a version control system
-   |
-LL |     (1, 2, dbg!(3, 4));
-   |     ~~~~~~~~~~~~~~~~~~
-
-error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:34:5
+  --> tests/ui/dbg_macro/dbg_macro.rs:26:5
    |
 LL |     dbg!(1, 2, 3, 4, 5);
    |     ^^^^^^^^^^^^^^^^^^^
@@ -112,7 +78,7 @@ LL |     (1, 2, 3, 4, 5);
    |     ~~~~~~~~~~~~~~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:55:5
+  --> tests/ui/dbg_macro/dbg_macro.rs:48:5
    |
 LL |     dbg!();
    |     ^^^^^^^
@@ -124,7 +90,7 @@ LL +
    |
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:58:13
+  --> tests/ui/dbg_macro/dbg_macro.rs:51:13
    |
 LL |     let _ = dbg!();
    |             ^^^^^^
@@ -135,7 +101,7 @@ LL |     let _ = ();
    |             ~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:60:9
+  --> tests/ui/dbg_macro/dbg_macro.rs:53:9
    |
 LL |     bar(dbg!());
    |         ^^^^^^
@@ -146,7 +112,7 @@ LL |     bar(());
    |         ~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:62:10
+  --> tests/ui/dbg_macro/dbg_macro.rs:55:10
    |
 LL |     foo!(dbg!());
    |          ^^^^^^
@@ -157,7 +123,7 @@ LL |     foo!(());
    |          ~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:64:16
+  --> tests/ui/dbg_macro/dbg_macro.rs:57:16
    |
 LL |     foo2!(foo!(dbg!()));
    |                ^^^^^^
@@ -168,7 +134,23 @@ LL |     foo2!(foo!(()));
    |                ~~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:86:9
+  --> tests/ui/dbg_macro/dbg_macro.rs:43:13
+   |
+LL |             dbg!();
+   |             ^^^^^^^
+...
+LL |     expand_to_dbg!();
+   |     ---------------- in this macro invocation
+   |
+   = note: this error originates in the macro `expand_to_dbg` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: remove the invocation before committing it to a version control system
+   |
+LL -             dbg!();
+LL +             
+   |
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro.rs:79:9
    |
 LL |         dbg!(2);
    |         ^^^^^^^
@@ -179,7 +161,7 @@ LL |         2;
    |         ~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:93:5
+  --> tests/ui/dbg_macro/dbg_macro.rs:86:5
    |
 LL |     dbg!(1);
    |     ^^^^^^^
@@ -190,7 +172,7 @@ LL |     1;
    |     ~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:99:5
+  --> tests/ui/dbg_macro/dbg_macro.rs:92:5
    |
 LL |     dbg!(1);
    |     ^^^^^^^
@@ -201,7 +183,7 @@ LL |     1;
    |     ~
 
 error: the `dbg!` macro is intended as a debugging tool
-  --> tests/ui/dbg_macro/dbg_macro.rs:106:9
+  --> tests/ui/dbg_macro/dbg_macro.rs:99:9
    |
 LL |         dbg!(1);
    |         ^^^^^^^
@@ -211,5 +193,27 @@ help: remove the invocation before committing it to a version control system
 LL |         1;
    |         ~
 
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro.rs:106:31
+   |
+LL |         println!("dbg: {:?}", dbg!(s));
+   |                               ^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |         println!("dbg: {:?}", s);
+   |                               ~
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro.rs:108:22
+   |
+LL |         print!("{}", dbg!(s));
+   |                      ^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |         print!("{}", s);
+   |                      ~
+
 error: aborting due to 19 previous errors
 
diff --git a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro_unfixable.rs b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro_unfixable.rs
new file mode 100644
index 00000000000..0e83766ccae
--- /dev/null
+++ b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro_unfixable.rs
@@ -0,0 +1,12 @@
+//@no-rustfix
+#![warn(clippy::dbg_macro)]
+
+#[path = "auxiliary/submodule.rs"]
+mod submodule;
+
+fn main() {
+    dbg!(dbg!(dbg!(42)));
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+    dbg!(1, 2, dbg!(3, 4));
+    //~^ ERROR: the `dbg!` macro is intended as a debugging tool
+}
diff --git a/src/tools/clippy/tests/ui/dbg_macro/dbg_macro_unfixable.stderr b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro_unfixable.stderr
new file mode 100644
index 00000000000..d21595c2fcd
--- /dev/null
+++ b/src/tools/clippy/tests/ui/dbg_macro/dbg_macro_unfixable.stderr
@@ -0,0 +1,71 @@
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/auxiliary/submodule.rs:2:5
+   |
+LL |     dbg!();
+   |     ^^^^^^^
+   |
+   = note: `-D clippy::dbg-macro` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::dbg_macro)]`
+help: remove the invocation before committing it to a version control system
+   |
+LL -     dbg!();
+LL +     
+   |
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro_unfixable.rs:8:5
+   |
+LL |     dbg!(dbg!(dbg!(42)));
+   |     ^^^^^^^^^^^^^^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |     dbg!(dbg!(42));
+   |     ~~~~~~~~~~~~~~
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro_unfixable.rs:8:10
+   |
+LL |     dbg!(dbg!(dbg!(42)));
+   |          ^^^^^^^^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |     dbg!(dbg!(42));
+   |          ~~~~~~~~
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro_unfixable.rs:8:15
+   |
+LL |     dbg!(dbg!(dbg!(42)));
+   |               ^^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |     dbg!(dbg!(42));
+   |               ~~
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro_unfixable.rs:10:5
+   |
+LL |     dbg!(1, 2, dbg!(3, 4));
+   |     ^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |     (1, 2, dbg!(3, 4));
+   |     ~~~~~~~~~~~~~~~~~~
+
+error: the `dbg!` macro is intended as a debugging tool
+  --> tests/ui/dbg_macro/dbg_macro_unfixable.rs:10:16
+   |
+LL |     dbg!(1, 2, dbg!(3, 4));
+   |                ^^^^^^^^^^
+   |
+help: remove the invocation before committing it to a version control system
+   |
+LL |     dbg!(1, 2, (3, 4));
+   |                ~~~~~~
+
+error: aborting due to 6 previous errors
+
diff --git a/src/tools/clippy/tests/ui/doc/issue_10262.fixed b/src/tools/clippy/tests/ui/doc/issue_10262.fixed
new file mode 100644
index 00000000000..5d067736d55
--- /dev/null
+++ b/src/tools/clippy/tests/ui/doc/issue_10262.fixed
@@ -0,0 +1,12 @@
+#![warn(clippy::doc_markdown)]
+
+// Should only warn for the first line!
+/// `AviSynth` documentation:
+//~^ ERROR: item in documentation is missing backticks
+///
+/// > AvisynthPluginInit3 may be called more than once with different IScriptEnvironments.
+///
+/// <blockquote>bla AvisynthPluginInit3 bla</blockquote>
+///
+/// <q>bla AvisynthPluginInit3 bla</q>
+pub struct Foo;
diff --git a/src/tools/clippy/tests/ui/doc/issue_10262.rs b/src/tools/clippy/tests/ui/doc/issue_10262.rs
new file mode 100644
index 00000000000..e2cbd938d5d
--- /dev/null
+++ b/src/tools/clippy/tests/ui/doc/issue_10262.rs
@@ -0,0 +1,12 @@
+#![warn(clippy::doc_markdown)]
+
+// Should only warn for the first line!
+/// AviSynth documentation:
+//~^ ERROR: item in documentation is missing backticks
+///
+/// > AvisynthPluginInit3 may be called more than once with different IScriptEnvironments.
+///
+/// <blockquote>bla AvisynthPluginInit3 bla</blockquote>
+///
+/// <q>bla AvisynthPluginInit3 bla</q>
+pub struct Foo;
diff --git a/src/tools/clippy/tests/ui/doc/issue_10262.stderr b/src/tools/clippy/tests/ui/doc/issue_10262.stderr
new file mode 100644
index 00000000000..f43d9551e94
--- /dev/null
+++ b/src/tools/clippy/tests/ui/doc/issue_10262.stderr
@@ -0,0 +1,15 @@
+error: item in documentation is missing backticks
+  --> tests/ui/doc/issue_10262.rs:4:5
+   |
+LL | /// AviSynth documentation:
+   |     ^^^^^^^^
+   |
+   = note: `-D clippy::doc-markdown` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::doc_markdown)]`
+help: try
+   |
+LL | /// `AviSynth` documentation:
+   |     ~~~~~~~~~~
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/clippy/tests/ui/duplicated_attributes.rs b/src/tools/clippy/tests/ui/duplicated_attributes.rs
new file mode 100644
index 00000000000..0f036c684c1
--- /dev/null
+++ b/src/tools/clippy/tests/ui/duplicated_attributes.rs
@@ -0,0 +1,17 @@
+#![warn(clippy::duplicated_attributes)]
+#![cfg(any(unix, windows))]
+#![allow(dead_code)]
+#![allow(dead_code)] //~ ERROR: duplicated attribute
+#![cfg(any(unix, windows))]
+//~^ ERROR: duplicated attribute
+//~| ERROR: duplicated attribute
+
+#[cfg(any(unix, windows, target_os = "linux"))]
+#[allow(dead_code)]
+#[allow(dead_code)] //~ ERROR: duplicated attribute
+#[cfg(any(unix, windows, target_os = "linux"))]
+//~^ ERROR: duplicated attribute
+//~| ERROR: duplicated attribute
+fn foo() {}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/duplicated_attributes.stderr b/src/tools/clippy/tests/ui/duplicated_attributes.stderr
new file mode 100644
index 00000000000..1c6578dbb43
--- /dev/null
+++ b/src/tools/clippy/tests/ui/duplicated_attributes.stderr
@@ -0,0 +1,123 @@
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:4:10
+   |
+LL | #![allow(dead_code)]
+   |          ^^^^^^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:3:10
+   |
+LL | #![allow(dead_code)]
+   |          ^^^^^^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:4:10
+   |
+LL | #![allow(dead_code)]
+   |          ^^^^^^^^^
+   = note: `-D clippy::duplicated-attributes` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::duplicated_attributes)]`
+
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:5:12
+   |
+LL | #![cfg(any(unix, windows))]
+   |            ^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:2:12
+   |
+LL | #![cfg(any(unix, windows))]
+   |            ^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:5:12
+   |
+LL | #![cfg(any(unix, windows))]
+   |            ^^^^
+
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:5:18
+   |
+LL | #![cfg(any(unix, windows))]
+   |                  ^^^^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:2:18
+   |
+LL | #![cfg(any(unix, windows))]
+   |                  ^^^^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:5:18
+   |
+LL | #![cfg(any(unix, windows))]
+   |                  ^^^^^^^
+
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:11:9
+   |
+LL | #[allow(dead_code)]
+   |         ^^^^^^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:10:9
+   |
+LL | #[allow(dead_code)]
+   |         ^^^^^^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:11:9
+   |
+LL | #[allow(dead_code)]
+   |         ^^^^^^^^^
+
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:12:11
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |           ^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:9:11
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |           ^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:12:11
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |           ^^^^
+
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:12:17
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |                 ^^^^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:9:17
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |                 ^^^^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:12:17
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |                 ^^^^^^^
+
+error: duplicated attribute
+  --> tests/ui/duplicated_attributes.rs:12:26
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |                          ^^^^^^^^^^^^^^^^^^^
+   |
+note: first defined here
+  --> tests/ui/duplicated_attributes.rs:9:26
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |                          ^^^^^^^^^^^^^^^^^^^
+help: remove this attribute
+  --> tests/ui/duplicated_attributes.rs:12:26
+   |
+LL | #[cfg(any(unix, windows, target_os = "linux"))]
+   |                          ^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 7 previous errors
+
diff --git a/src/tools/clippy/tests/ui/else_if_without_else.rs b/src/tools/clippy/tests/ui/else_if_without_else.rs
index e7786f7dd27..b04c22fa2ae 100644
--- a/src/tools/clippy/tests/ui/else_if_without_else.rs
+++ b/src/tools/clippy/tests/ui/else_if_without_else.rs
@@ -1,7 +1,5 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
-#![warn(clippy::all)]
 #![warn(clippy::else_if_without_else)]
+#![allow(clippy::collapsible_else_if)]
 
 fn bla1() -> bool {
     unimplemented!()
@@ -12,6 +10,12 @@ fn bla2() -> bool {
 fn bla3() -> bool {
     unimplemented!()
 }
+fn bla4() -> bool {
+    unimplemented!()
+}
+fn bla5() -> bool {
+    unimplemented!()
+}
 
 fn main() {
     if bla1() {
@@ -57,4 +61,62 @@ fn main() {
         //~^ ERROR: `if` expression with an `else if`, but without a final `else`
         println!("else if 2");
     }
+
+    if bla1() {
+        println!("if");
+    } else if bla2() {
+        println!("else if 1");
+    } else if bla3() {
+        println!("else if 2");
+    } else if bla4() {
+        println!("else if 3");
+    } else if bla5() {
+        println!("else if 4");
+    } else {
+        println!("else");
+    }
+
+    if bla1() {
+        println!("if");
+    } else if bla2() {
+        println!("else if 1");
+    } else if bla3() {
+        println!("else if 2");
+    } else if bla4() {
+        println!("else if 3");
+    } else if bla5() {
+        //~^ ERROR: `if` expression with an `else if`, but without a final `else`
+        println!("else if 4");
+    }
+
+    if bla1() {
+        println!("if");
+    } else if bla2() {
+        println!("else if 1");
+    } else {
+        if bla3() {
+            println!("else if 2");
+        } else if bla4() {
+            println!("else if 3");
+        } else if bla5() {
+            println!("else if 4");
+        } else {
+            println!("else");
+        }
+    }
+
+    if bla1() {
+        println!("if");
+    } else if bla2() {
+        println!("else if 1");
+    } else {
+        if bla3() {
+            println!("else if 2");
+        } else if bla4() {
+            println!("else if 3");
+        } else if bla5() {
+            //~^ ERROR: `if` expression with an `else if`, but without a final `else`
+            println!("else if 4");
+        }
+    }
 }
diff --git a/src/tools/clippy/tests/ui/else_if_without_else.stderr b/src/tools/clippy/tests/ui/else_if_without_else.stderr
index 3bb840f39e7..bc717485229 100644
--- a/src/tools/clippy/tests/ui/else_if_without_else.stderr
+++ b/src/tools/clippy/tests/ui/else_if_without_else.stderr
@@ -1,5 +1,5 @@
 error: `if` expression with an `else if`, but without a final `else`
-  --> tests/ui/else_if_without_else.rs:47:12
+  --> tests/ui/else_if_without_else.rs:51:12
    |
 LL |       } else if bla2() {
    |  ____________^
@@ -13,7 +13,7 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::else_if_without_else)]`
 
 error: `if` expression with an `else if`, but without a final `else`
-  --> tests/ui/else_if_without_else.rs:56:12
+  --> tests/ui/else_if_without_else.rs:60:12
    |
 LL |       } else if bla3() {
    |  ____________^
@@ -24,5 +24,29 @@ LL | |     }
    |
    = help: add an `else` block here
 
-error: aborting due to 2 previous errors
+error: `if` expression with an `else if`, but without a final `else`
+  --> tests/ui/else_if_without_else.rs:87:12
+   |
+LL |       } else if bla5() {
+   |  ____________^
+LL | |
+LL | |         println!("else if 4");
+LL | |     }
+   | |_____^
+   |
+   = help: add an `else` block here
+
+error: `if` expression with an `else if`, but without a final `else`
+  --> tests/ui/else_if_without_else.rs:117:16
+   |
+LL |           } else if bla5() {
+   |  ________________^
+LL | |
+LL | |             println!("else if 4");
+LL | |         }
+   | |_________^
+   |
+   = help: add an `else` block here
+
+error: aborting due to 4 previous errors
 
diff --git a/src/tools/clippy/tests/ui/empty_docs.rs b/src/tools/clippy/tests/ui/empty_docs.rs
index 272fab7d5ca..00e64eebc5f 100644
--- a/src/tools/clippy/tests/ui/empty_docs.rs
+++ b/src/tools/clippy/tests/ui/empty_docs.rs
@@ -1,6 +1,9 @@
+//@aux-build:proc_macro_attr.rs
+
 #![allow(unused)]
 #![warn(clippy::empty_docs)]
 #![allow(clippy::mixed_attributes_style)]
+#![feature(extern_types)]
 
 mod outer {
     //!
@@ -67,3 +70,17 @@ mod outer {
         y: i32,
     }
 }
+
+mod issue_12377 {
+    use proc_macro_attr::with_empty_docs;
+
+    #[with_empty_docs]
+    extern "C" {
+        type Test;
+    }
+
+    #[with_empty_docs]
+    struct Foo {
+        a: u8,
+    }
+}
diff --git a/src/tools/clippy/tests/ui/empty_docs.stderr b/src/tools/clippy/tests/ui/empty_docs.stderr
index f12aead6aa7..28ebea22c5d 100644
--- a/src/tools/clippy/tests/ui/empty_docs.stderr
+++ b/src/tools/clippy/tests/ui/empty_docs.stderr
@@ -1,5 +1,5 @@
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:6:5
+  --> tests/ui/empty_docs.rs:9:5
    |
 LL |     //!
    |     ^^^
@@ -9,7 +9,7 @@ LL |     //!
    = help: to override `-D warnings` add `#[allow(clippy::empty_docs)]`
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:14:5
+  --> tests/ui/empty_docs.rs:17:5
    |
 LL |     ///
    |     ^^^
@@ -17,7 +17,7 @@ LL |     ///
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:16:9
+  --> tests/ui/empty_docs.rs:19:9
    |
 LL |         ///
    |         ^^^
@@ -25,7 +25,7 @@ LL |         ///
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:27:5
+  --> tests/ui/empty_docs.rs:30:5
    |
 LL |     #[doc = ""]
    |     ^^^^^^^^^^^
@@ -33,7 +33,7 @@ LL |     #[doc = ""]
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:30:5
+  --> tests/ui/empty_docs.rs:33:5
    |
 LL | /     #[doc = ""]
 LL | |     #[doc = ""]
@@ -42,7 +42,7 @@ LL | |     #[doc = ""]
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:37:5
+  --> tests/ui/empty_docs.rs:40:5
    |
 LL |     ///
    |     ^^^
@@ -50,7 +50,7 @@ LL |     ///
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:50:13
+  --> tests/ui/empty_docs.rs:53:13
    |
 LL |             /*! */
    |             ^^^^^^
@@ -58,7 +58,7 @@ LL |             /*! */
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:58:13
+  --> tests/ui/empty_docs.rs:61:13
    |
 LL |             ///
    |             ^^^
@@ -66,7 +66,7 @@ LL |             ///
    = help: consider removing or filling it
 
 error: empty doc comment
-  --> tests/ui/empty_docs.rs:66:9
+  --> tests/ui/empty_docs.rs:69:9
    |
 LL |         ///
    |         ^^^
diff --git a/src/tools/clippy/tests/ui/empty_line_after_doc_comments.rs b/src/tools/clippy/tests/ui/empty_line_after_doc_comments.rs
index e843770f578..dd78491749c 100644
--- a/src/tools/clippy/tests/ui/empty_line_after_doc_comments.rs
+++ b/src/tools/clippy/tests/ui/empty_line_after_doc_comments.rs
@@ -1,6 +1,6 @@
 //@aux-build:proc_macro_attr.rs
 #![warn(clippy::empty_line_after_doc_comments)]
-#![allow(clippy::assertions_on_constants)]
+#![allow(clippy::assertions_on_constants, clippy::duplicated_attributes)]
 #![feature(custom_inner_attributes)]
 #![rustfmt::skip]
 
diff --git a/src/tools/clippy/tests/ui/empty_line_after_outer_attribute.rs b/src/tools/clippy/tests/ui/empty_line_after_outer_attribute.rs
index 269e66ea0a8..f147cf2cd5d 100644
--- a/src/tools/clippy/tests/ui/empty_line_after_outer_attribute.rs
+++ b/src/tools/clippy/tests/ui/empty_line_after_outer_attribute.rs
@@ -1,6 +1,6 @@
 //@aux-build:proc_macro_attr.rs
 #![warn(clippy::empty_line_after_outer_attr)]
-#![allow(clippy::assertions_on_constants)]
+#![allow(clippy::assertions_on_constants, clippy::duplicated_attributes)]
 #![feature(custom_inner_attributes)]
 #![rustfmt::skip]
 
diff --git a/src/tools/clippy/tests/ui/entry.fixed b/src/tools/clippy/tests/ui/entry.fixed
index 71ec13f4610..abdfae2a3e1 100644
--- a/src/tools/clippy/tests/ui/entry.fixed
+++ b/src/tools/clippy/tests/ui/entry.fixed
@@ -176,4 +176,14 @@ pub fn issue_11935() {
     }
 }
 
+fn issue12489(map: &mut HashMap<u64, u64>) -> Option<()> {
+    if let std::collections::hash_map::Entry::Vacant(e) = map.entry(1) {
+        let Some(1) = Some(2) else {
+            return None;
+        };
+        e.insert(42);
+    }
+    Some(())
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/entry.rs b/src/tools/clippy/tests/ui/entry.rs
index 86092b7c055..7774f99a2a2 100644
--- a/src/tools/clippy/tests/ui/entry.rs
+++ b/src/tools/clippy/tests/ui/entry.rs
@@ -180,4 +180,14 @@ pub fn issue_11935() {
     }
 }
 
+fn issue12489(map: &mut HashMap<u64, u64>) -> Option<()> {
+    if !map.contains_key(&1) {
+        let Some(1) = Some(2) else {
+            return None;
+        };
+        map.insert(1, 42);
+    }
+    Some(())
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/entry.stderr b/src/tools/clippy/tests/ui/entry.stderr
index ef4c36bcf54..fb467676606 100644
--- a/src/tools/clippy/tests/ui/entry.stderr
+++ b/src/tools/clippy/tests/ui/entry.stderr
@@ -214,5 +214,26 @@ LL +         v
 LL +     });
    |
 
-error: aborting due to 10 previous errors
+error: usage of `contains_key` followed by `insert` on a `HashMap`
+  --> tests/ui/entry.rs:184:5
+   |
+LL | /     if !map.contains_key(&1) {
+LL | |         let Some(1) = Some(2) else {
+LL | |             return None;
+LL | |         };
+LL | |         map.insert(1, 42);
+LL | |     }
+   | |_____^
+   |
+help: try
+   |
+LL ~     if let std::collections::hash_map::Entry::Vacant(e) = map.entry(1) {
+LL +         let Some(1) = Some(2) else {
+LL +             return None;
+LL +         };
+LL +         e.insert(42);
+LL +     }
+   |
+
+error: aborting due to 11 previous errors
 
diff --git a/src/tools/clippy/tests/ui/integer_division_remainder_used.rs b/src/tools/clippy/tests/ui/integer_division_remainder_used.rs
new file mode 100644
index 00000000000..5d1b02095d1
--- /dev/null
+++ b/src/tools/clippy/tests/ui/integer_division_remainder_used.rs
@@ -0,0 +1,41 @@
+#![warn(clippy::integer_division_remainder_used)]
+#![allow(unused_variables)]
+#![allow(clippy::op_ref)]
+
+struct CustomOps(pub i32);
+impl std::ops::Div for CustomOps {
+    type Output = Self;
+
+    fn div(self, rhs: Self) -> Self::Output {
+        Self(self.0 / rhs.0)
+    }
+}
+impl std::ops::Rem for CustomOps {
+    type Output = Self;
+
+    fn rem(self, rhs: Self) -> Self::Output {
+        Self(self.0 % rhs.0)
+    }
+}
+
+fn main() {
+    // should trigger
+    let a = 10;
+    let b = 5;
+    let c = a / b;
+    let d = a % b;
+    let e = &a / b;
+    let f = a % &b;
+    let g = &a / &b;
+    let h = &10 % b;
+    let i = a / &4;
+
+    // should not trigger on custom Div and Rem
+    let w = CustomOps(3);
+    let x = CustomOps(4);
+    let y = w / x;
+
+    let w = CustomOps(3);
+    let x = CustomOps(4);
+    let z = w % x;
+}
diff --git a/src/tools/clippy/tests/ui/integer_division_remainder_used.stderr b/src/tools/clippy/tests/ui/integer_division_remainder_used.stderr
new file mode 100644
index 00000000000..8adfda28893
--- /dev/null
+++ b/src/tools/clippy/tests/ui/integer_division_remainder_used.stderr
@@ -0,0 +1,59 @@
+error: use of / has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:10:14
+   |
+LL |         Self(self.0 / rhs.0)
+   |              ^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::integer-division-remainder-used` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::integer_division_remainder_used)]`
+
+error: use of % has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:17:14
+   |
+LL |         Self(self.0 % rhs.0)
+   |              ^^^^^^^^^^^^^^
+
+error: use of / has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:25:13
+   |
+LL |     let c = a / b;
+   |             ^^^^^
+
+error: use of % has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:26:13
+   |
+LL |     let d = a % b;
+   |             ^^^^^
+
+error: use of / has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:27:13
+   |
+LL |     let e = &a / b;
+   |             ^^^^^^
+
+error: use of % has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:28:13
+   |
+LL |     let f = a % &b;
+   |             ^^^^^^
+
+error: use of / has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:29:13
+   |
+LL |     let g = &a / &b;
+   |             ^^^^^^^
+
+error: use of % has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:30:13
+   |
+LL |     let h = &10 % b;
+   |             ^^^^^^^
+
+error: use of / has been disallowed in this context
+  --> tests/ui/integer_division_remainder_used.rs:31:13
+   |
+LL |     let i = a / &4;
+   |             ^^^^^^
+
+error: aborting due to 9 previous errors
+
diff --git a/src/tools/clippy/tests/ui/iter_nth.fixed b/src/tools/clippy/tests/ui/iter_nth.fixed
new file mode 100644
index 00000000000..aff3731a883
--- /dev/null
+++ b/src/tools/clippy/tests/ui/iter_nth.fixed
@@ -0,0 +1,60 @@
+//@aux-build:option_helpers.rs
+
+#![warn(clippy::iter_nth)]
+#![allow(clippy::useless_vec)]
+
+#[macro_use]
+extern crate option_helpers;
+
+use option_helpers::IteratorFalsePositives;
+use std::collections::VecDeque;
+
+/// Struct to generate false positives for things with `.iter()`.
+#[derive(Copy, Clone)]
+struct HasIter;
+
+impl HasIter {
+    fn iter(self) -> IteratorFalsePositives {
+        IteratorFalsePositives { foo: 0 }
+    }
+
+    fn iter_mut(self) -> IteratorFalsePositives {
+        IteratorFalsePositives { foo: 0 }
+    }
+}
+
+/// Checks implementation of `ITER_NTH` lint.
+fn iter_nth() {
+    let mut some_vec = vec![0, 1, 2, 3];
+    let mut boxed_slice: Box<[u8]> = Box::new([0, 1, 2, 3]);
+    let mut some_vec_deque: VecDeque<_> = some_vec.iter().cloned().collect();
+
+    {
+        // Make sure we lint `.iter()` for relevant types.
+        let bad_vec = some_vec.get(3);
+        let bad_slice = &some_vec[..].get(3);
+        let bad_boxed_slice = boxed_slice.get(3);
+        let bad_vec_deque = some_vec_deque.get(3);
+    }
+
+    {
+        // Make sure we lint `.iter_mut()` for relevant types.
+        let bad_vec = some_vec.get_mut(3);
+    }
+    {
+        let bad_slice = &some_vec[..].get_mut(3);
+    }
+    {
+        let bad_vec_deque = some_vec_deque.get_mut(3);
+    }
+
+    let vec_ref = &Vec::<String>::new();
+    vec_ref.get(3);
+
+    // Make sure we don't lint for non-relevant types.
+    let false_positive = HasIter;
+    let ok = false_positive.iter().nth(3);
+    let ok_mut = false_positive.iter_mut().nth(3);
+}
+
+fn main() {}
diff --git a/src/tools/clippy/tests/ui/iter_nth.rs b/src/tools/clippy/tests/ui/iter_nth.rs
index 7c567bb81d8..89d68044ddd 100644
--- a/src/tools/clippy/tests/ui/iter_nth.rs
+++ b/src/tools/clippy/tests/ui/iter_nth.rs
@@ -48,6 +48,9 @@ fn iter_nth() {
         let bad_vec_deque = some_vec_deque.iter_mut().nth(3);
     }
 
+    let vec_ref = &Vec::<String>::new();
+    vec_ref.iter().nth(3);
+
     // Make sure we don't lint for non-relevant types.
     let false_positive = HasIter;
     let ok = false_positive.iter().nth(3);
diff --git a/src/tools/clippy/tests/ui/iter_nth.stderr b/src/tools/clippy/tests/ui/iter_nth.stderr
index c5dd0c99727..178463f5347 100644
--- a/src/tools/clippy/tests/ui/iter_nth.stderr
+++ b/src/tools/clippy/tests/ui/iter_nth.stderr
@@ -4,9 +4,12 @@ error: called `.iter().nth()` on a `Vec`
 LL |         let bad_vec = some_vec.iter().nth(3);
    |                       ^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get()` is both faster and more readable
    = note: `-D clippy::iter-nth` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::iter_nth)]`
+help: `get` is equivalent but more concise
+   |
+LL |         let bad_vec = some_vec.get(3);
+   |                                ~~~
 
 error: called `.iter().nth()` on a slice
   --> tests/ui/iter_nth.rs:35:26
@@ -14,7 +17,10 @@ error: called `.iter().nth()` on a slice
 LL |         let bad_slice = &some_vec[..].iter().nth(3);
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get()` is both faster and more readable
+help: `get` is equivalent but more concise
+   |
+LL |         let bad_slice = &some_vec[..].get(3);
+   |                                       ~~~
 
 error: called `.iter().nth()` on a slice
   --> tests/ui/iter_nth.rs:36:31
@@ -22,7 +28,10 @@ error: called `.iter().nth()` on a slice
 LL |         let bad_boxed_slice = boxed_slice.iter().nth(3);
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get()` is both faster and more readable
+help: `get` is equivalent but more concise
+   |
+LL |         let bad_boxed_slice = boxed_slice.get(3);
+   |                                           ~~~
 
 error: called `.iter().nth()` on a `VecDeque`
   --> tests/ui/iter_nth.rs:37:29
@@ -30,7 +39,10 @@ error: called `.iter().nth()` on a `VecDeque`
 LL |         let bad_vec_deque = some_vec_deque.iter().nth(3);
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get()` is both faster and more readable
+help: `get` is equivalent but more concise
+   |
+LL |         let bad_vec_deque = some_vec_deque.get(3);
+   |                                            ~~~
 
 error: called `.iter_mut().nth()` on a `Vec`
   --> tests/ui/iter_nth.rs:42:23
@@ -38,7 +50,10 @@ error: called `.iter_mut().nth()` on a `Vec`
 LL |         let bad_vec = some_vec.iter_mut().nth(3);
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get_mut()` is both faster and more readable
+help: `get_mut` is equivalent but more concise
+   |
+LL |         let bad_vec = some_vec.get_mut(3);
+   |                                ~~~~~~~
 
 error: called `.iter_mut().nth()` on a slice
   --> tests/ui/iter_nth.rs:45:26
@@ -46,7 +61,10 @@ error: called `.iter_mut().nth()` on a slice
 LL |         let bad_slice = &some_vec[..].iter_mut().nth(3);
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get_mut()` is both faster and more readable
+help: `get_mut` is equivalent but more concise
+   |
+LL |         let bad_slice = &some_vec[..].get_mut(3);
+   |                                       ~~~~~~~
 
 error: called `.iter_mut().nth()` on a `VecDeque`
   --> tests/ui/iter_nth.rs:48:29
@@ -54,7 +72,21 @@ error: called `.iter_mut().nth()` on a `VecDeque`
 LL |         let bad_vec_deque = some_vec_deque.iter_mut().nth(3);
    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = help: calling `.get_mut()` is both faster and more readable
+help: `get_mut` is equivalent but more concise
+   |
+LL |         let bad_vec_deque = some_vec_deque.get_mut(3);
+   |                                            ~~~~~~~
+
+error: called `.iter().nth()` on a `Vec`
+  --> tests/ui/iter_nth.rs:52:5
+   |
+LL |     vec_ref.iter().nth(3);
+   |     ^^^^^^^^^^^^^^^^^^^^^
+   |
+help: `get` is equivalent but more concise
+   |
+LL |     vec_ref.get(3);
+   |             ~~~
 
-error: aborting due to 7 previous errors
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/len_zero.fixed b/src/tools/clippy/tests/ui/len_zero.fixed
index 745fc7e1a8b..c16d7a26616 100644
--- a/src/tools/clippy/tests/ui/len_zero.fixed
+++ b/src/tools/clippy/tests/ui/len_zero.fixed
@@ -1,5 +1,11 @@
 #![warn(clippy::len_zero)]
-#![allow(dead_code, unused, clippy::needless_if, clippy::len_without_is_empty)]
+#![allow(
+    dead_code,
+    unused,
+    clippy::needless_if,
+    clippy::len_without_is_empty,
+    clippy::const_is_empty
+)]
 
 extern crate core;
 use core::ops::Deref;
diff --git a/src/tools/clippy/tests/ui/len_zero.rs b/src/tools/clippy/tests/ui/len_zero.rs
index 048ad2f4fd3..5c49a5abf81 100644
--- a/src/tools/clippy/tests/ui/len_zero.rs
+++ b/src/tools/clippy/tests/ui/len_zero.rs
@@ -1,5 +1,11 @@
 #![warn(clippy::len_zero)]
-#![allow(dead_code, unused, clippy::needless_if, clippy::len_without_is_empty)]
+#![allow(
+    dead_code,
+    unused,
+    clippy::needless_if,
+    clippy::len_without_is_empty,
+    clippy::const_is_empty
+)]
 
 extern crate core;
 use core::ops::Deref;
diff --git a/src/tools/clippy/tests/ui/len_zero.stderr b/src/tools/clippy/tests/ui/len_zero.stderr
index b1f04c94de6..dd07a85d62c 100644
--- a/src/tools/clippy/tests/ui/len_zero.stderr
+++ b/src/tools/clippy/tests/ui/len_zero.stderr
@@ -1,5 +1,5 @@
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:82:8
+  --> tests/ui/len_zero.rs:88:8
    |
 LL |     if x.len() == 0 {
    |        ^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `x.is_empty()`
@@ -8,13 +8,13 @@ LL |     if x.len() == 0 {
    = help: to override `-D warnings` add `#[allow(clippy::len_zero)]`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:86:8
+  --> tests/ui/len_zero.rs:92:8
    |
 LL |     if "".len() == 0 {}
    |        ^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `"".is_empty()`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:95:20
+  --> tests/ui/len_zero.rs:101:20
    |
 LL |     println!("{}", *s1 == "");
    |                    ^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `s1.is_empty()`
@@ -23,121 +23,121 @@ LL |     println!("{}", *s1 == "");
    = help: to override `-D warnings` add `#[allow(clippy::comparison_to_empty)]`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:96:20
+  --> tests/ui/len_zero.rs:102:20
    |
 LL |     println!("{}", **s2 == "");
    |                    ^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `s2.is_empty()`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:97:20
+  --> tests/ui/len_zero.rs:103:20
    |
 LL |     println!("{}", ***s3 == "");
    |                    ^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `s3.is_empty()`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:98:20
+  --> tests/ui/len_zero.rs:104:20
    |
 LL |     println!("{}", ****s4 == "");
    |                    ^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `s4.is_empty()`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:99:20
+  --> tests/ui/len_zero.rs:105:20
    |
 LL |     println!("{}", *****s5 == "");
    |                    ^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `s5.is_empty()`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:100:20
+  --> tests/ui/len_zero.rs:106:20
    |
 LL |     println!("{}", ******(s6) == "");
    |                    ^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `(s6).is_empty()`
 
 error: comparison to empty slice
-  --> tests/ui/len_zero.rs:103:20
+  --> tests/ui/len_zero.rs:109:20
    |
 LL |     println!("{}", &**d2s == "");
    |                    ^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `(**d2s).is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:118:8
+  --> tests/ui/len_zero.rs:124:8
    |
 LL |     if has_is_empty.len() == 0 {
    |        ^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:121:8
+  --> tests/ui/len_zero.rs:127:8
    |
 LL |     if has_is_empty.len() != 0 {
    |        ^^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:124:8
+  --> tests/ui/len_zero.rs:130:8
    |
 LL |     if has_is_empty.len() > 0 {
    |        ^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to one
-  --> tests/ui/len_zero.rs:127:8
+  --> tests/ui/len_zero.rs:133:8
    |
 LL |     if has_is_empty.len() < 1 {
    |        ^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
 
 error: length comparison to one
-  --> tests/ui/len_zero.rs:130:8
+  --> tests/ui/len_zero.rs:136:8
    |
 LL |     if has_is_empty.len() >= 1 {
    |        ^^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:141:8
+  --> tests/ui/len_zero.rs:147:8
    |
 LL |     if 0 == has_is_empty.len() {
    |        ^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:144:8
+  --> tests/ui/len_zero.rs:150:8
    |
 LL |     if 0 != has_is_empty.len() {
    |        ^^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:147:8
+  --> tests/ui/len_zero.rs:153:8
    |
 LL |     if 0 < has_is_empty.len() {
    |        ^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to one
-  --> tests/ui/len_zero.rs:150:8
+  --> tests/ui/len_zero.rs:156:8
    |
 LL |     if 1 <= has_is_empty.len() {
    |        ^^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to one
-  --> tests/ui/len_zero.rs:153:8
+  --> tests/ui/len_zero.rs:159:8
    |
 LL |     if 1 > has_is_empty.len() {
    |        ^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:167:8
+  --> tests/ui/len_zero.rs:173:8
    |
 LL |     if with_is_empty.len() == 0 {
    |        ^^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `with_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:179:6
+  --> tests/ui/len_zero.rs:185:6
    |
 LL |     (has_is_empty.len() > 0).then(|| println!("This can happen."));
    |      ^^^^^^^^^^^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:180:6
+  --> tests/ui/len_zero.rs:186:6
    |
 LL |     (has_is_empty.len() == 0).then(|| println!("Or this!"));
    |      ^^^^^^^^^^^^^^^^^^^^^^^ help: using `is_empty` is clearer and more explicit: `has_is_empty.is_empty()`
 
 error: length comparison to zero
-  --> tests/ui/len_zero.rs:184:8
+  --> tests/ui/len_zero.rs:190:8
    |
 LL |     if b.len() != 0 {}
    |        ^^^^^^^^^^^^ help: using `!is_empty` is clearer and more explicit: `!b.is_empty()`
diff --git a/src/tools/clippy/tests/ui/let_if_seq.rs b/src/tools/clippy/tests/ui/let_if_seq.rs
index 9869d945299..a29d35880b8 100644
--- a/src/tools/clippy/tests/ui/let_if_seq.rs
+++ b/src/tools/clippy/tests/ui/let_if_seq.rs
@@ -57,6 +57,17 @@ fn early_return() -> u8 {
     foo
 }
 
+fn allow_works() -> i32 {
+    #[allow(clippy::useless_let_if_seq)]
+    let x;
+    if true {
+        x = 1;
+    } else {
+        x = 2;
+    }
+    x
+}
+
 fn main() {
     early_return();
     issue975();
diff --git a/src/tools/clippy/tests/ui/let_if_seq.stderr b/src/tools/clippy/tests/ui/let_if_seq.stderr
index 87ad20dc27e..41930108fb1 100644
--- a/src/tools/clippy/tests/ui/let_if_seq.stderr
+++ b/src/tools/clippy/tests/ui/let_if_seq.stderr
@@ -1,5 +1,5 @@
 error: `if _ { .. } else { .. }` is an expression
-  --> tests/ui/let_if_seq.rs:66:5
+  --> tests/ui/let_if_seq.rs:77:5
    |
 LL | /     let mut foo = 0;
 LL | |
@@ -14,7 +14,7 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::useless_let_if_seq)]`
 
 error: `if _ { .. } else { .. }` is an expression
-  --> tests/ui/let_if_seq.rs:73:5
+  --> tests/ui/let_if_seq.rs:84:5
    |
 LL | /     let mut bar = 0;
 LL | |
@@ -28,7 +28,7 @@ LL | |     }
    = note: you might not need `mut` at all
 
 error: `if _ { .. } else { .. }` is an expression
-  --> tests/ui/let_if_seq.rs:83:5
+  --> tests/ui/let_if_seq.rs:94:5
    |
 LL | /     let quz;
 LL | |
@@ -40,7 +40,7 @@ LL | |     }
    | |_____^ help: it is more idiomatic to write: `let quz = if f() { 42 } else { 0 };`
 
 error: `if _ { .. } else { .. }` is an expression
-  --> tests/ui/let_if_seq.rs:113:5
+  --> tests/ui/let_if_seq.rs:124:5
    |
 LL | /     let mut baz = 0;
 LL | |
diff --git a/src/tools/clippy/tests/ui/manual_let_else.rs b/src/tools/clippy/tests/ui/manual_let_else.rs
index 1fb252e3f97..2b36c3f3c2f 100644
--- a/src/tools/clippy/tests/ui/manual_let_else.rs
+++ b/src/tools/clippy/tests/ui/manual_let_else.rs
@@ -8,7 +8,8 @@
     clippy::never_loop,
     clippy::needless_if,
     clippy::diverging_sub_expression,
-    clippy::single_match
+    clippy::single_match,
+    clippy::manual_unwrap_or_default
 )]
 #![warn(clippy::manual_let_else)]
 //@no-rustfix
diff --git a/src/tools/clippy/tests/ui/manual_let_else.stderr b/src/tools/clippy/tests/ui/manual_let_else.stderr
index 7012c6b8891..55a410982ad 100644
--- a/src/tools/clippy/tests/ui/manual_let_else.stderr
+++ b/src/tools/clippy/tests/ui/manual_let_else.stderr
@@ -1,5 +1,5 @@
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:28:5
+  --> tests/ui/manual_let_else.rs:29:5
    |
 LL |     let v = if let Some(v_some) = g() { v_some } else { return };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { return };`
@@ -8,7 +8,7 @@ LL |     let v = if let Some(v_some) = g() { v_some } else { return };
    = help: to override `-D warnings` add `#[allow(clippy::manual_let_else)]`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:31:5
+  --> tests/ui/manual_let_else.rs:32:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -26,7 +26,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:38:5
+  --> tests/ui/manual_let_else.rs:39:5
    |
 LL | /     let v = if let Some(v) = g() {
 LL | |
@@ -47,25 +47,25 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:50:9
+  --> tests/ui/manual_let_else.rs:51:9
    |
 LL |         let v = if let Some(v_some) = g() { v_some } else { continue };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { continue };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:52:9
+  --> tests/ui/manual_let_else.rs:53:9
    |
 LL |         let v = if let Some(v_some) = g() { v_some } else { break };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { break };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:57:5
+  --> tests/ui/manual_let_else.rs:58:5
    |
 LL |     let v = if let Some(v_some) = g() { v_some } else { panic!() };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { panic!() };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:61:5
+  --> tests/ui/manual_let_else.rs:62:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -83,7 +83,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:69:5
+  --> tests/ui/manual_let_else.rs:70:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -101,7 +101,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:77:5
+  --> tests/ui/manual_let_else.rs:78:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -121,7 +121,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:86:5
+  --> tests/ui/manual_let_else.rs:87:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -141,7 +141,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:95:5
+  --> tests/ui/manual_let_else.rs:96:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -168,7 +168,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:111:5
+  --> tests/ui/manual_let_else.rs:112:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -190,7 +190,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:122:5
+  --> tests/ui/manual_let_else.rs:123:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -217,7 +217,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:138:5
+  --> tests/ui/manual_let_else.rs:139:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -239,7 +239,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:149:5
+  --> tests/ui/manual_let_else.rs:150:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -257,7 +257,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:157:5
+  --> tests/ui/manual_let_else.rs:158:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -278,7 +278,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:167:5
+  --> tests/ui/manual_let_else.rs:168:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -299,7 +299,7 @@ LL +     } };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:177:5
+  --> tests/ui/manual_let_else.rs:178:5
    |
 LL | /     let v = if let Some(v_some) = g() {
 LL | |
@@ -328,7 +328,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:195:5
+  --> tests/ui/manual_let_else.rs:196:5
    |
 LL | /     let (v, w) = if let Some(v_some) = g().map(|v| (v, 42)) {
 LL | |
@@ -346,7 +346,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:203:5
+  --> tests/ui/manual_let_else.rs:204:5
    |
 LL | /     let (w, S { v }) = if let (Some(v_some), w_some) = (g().map(|_| S { v: 0 }), 0) {
 LL | |
@@ -364,7 +364,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:213:13
+  --> tests/ui/manual_let_else.rs:214:13
    |
 LL |             let $n = if let Some(v) = $e { v } else { return };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some($n) = g() else { return };`
@@ -375,19 +375,19 @@ LL |     create_binding_if_some!(w, g());
    = note: this error originates in the macro `create_binding_if_some` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:222:5
+  --> tests/ui/manual_let_else.rs:223:5
    |
 LL |     let v = if let Variant::A(a, 0) = e() { a } else { return };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Variant::A(v, 0) = e() else { return };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:226:5
+  --> tests/ui/manual_let_else.rs:227:5
    |
 LL |     let mut v = if let Variant::B(b) = e() { b } else { return };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Variant::B(mut v) = e() else { return };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:231:5
+  --> tests/ui/manual_let_else.rs:232:5
    |
 LL | /     let v = if let Ok(Some(Variant::B(b))) | Err(Some(Variant::A(b, _))) = nested {
 LL | |
@@ -405,19 +405,19 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:238:5
+  --> tests/ui/manual_let_else.rs:239:5
    |
 LL |     let v = if let Variant::A(.., a) = e() { a } else { return };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Variant::A(.., v) = e() else { return };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:242:5
+  --> tests/ui/manual_let_else.rs:243:5
    |
 LL |     let w = if let (Some(v), ()) = (g(), ()) { v } else { return };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let (Some(w), ()) = (g(), ()) else { return };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:246:5
+  --> tests/ui/manual_let_else.rs:247:5
    |
 LL | /     let w = if let Some(S { v: x }) = Some(S { v: 0 }) {
 LL | |
@@ -435,7 +435,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:254:5
+  --> tests/ui/manual_let_else.rs:255:5
    |
 LL | /     let v = if let Some(S { v: x }) = Some(S { v: 0 }) {
 LL | |
@@ -453,7 +453,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:262:5
+  --> tests/ui/manual_let_else.rs:263:5
    |
 LL | /     let (x, S { v }, w) = if let Some(U { v, w, x }) = None::<U<S<()>>> {
 LL | |
@@ -471,7 +471,7 @@ LL +     };
    |
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:379:5
+  --> tests/ui/manual_let_else.rs:380:5
    |
 LL | /     let _ = match ff {
 LL | |
@@ -481,7 +481,7 @@ LL | |     };
    | |______^ help: consider writing: `let Some(_) = ff else { macro_call!() };`
 
 error: this could be rewritten as `let...else`
-  --> tests/ui/manual_let_else.rs:456:9
+  --> tests/ui/manual_let_else.rs:457:9
    |
 LL |         let v = if let Some(v_some) = g() { v_some } else { return };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { return };`
diff --git a/src/tools/clippy/tests/ui/manual_retain.fixed b/src/tools/clippy/tests/ui/manual_retain.fixed
index e359dfbb98c..5540029bf6b 100644
--- a/src/tools/clippy/tests/ui/manual_retain.fixed
+++ b/src/tools/clippy/tests/ui/manual_retain.fixed
@@ -1,5 +1,3 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::manual_retain)]
 #![allow(unused, clippy::redundant_clone)]
 use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
diff --git a/src/tools/clippy/tests/ui/manual_retain.rs b/src/tools/clippy/tests/ui/manual_retain.rs
index 931814f08b7..cee641d9d65 100644
--- a/src/tools/clippy/tests/ui/manual_retain.rs
+++ b/src/tools/clippy/tests/ui/manual_retain.rs
@@ -1,5 +1,3 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::manual_retain)]
 #![allow(unused, clippy::redundant_clone)]
 use std::collections::{BTreeMap, BTreeSet, BinaryHeap, HashMap, HashSet, VecDeque};
diff --git a/src/tools/clippy/tests/ui/manual_retain.stderr b/src/tools/clippy/tests/ui/manual_retain.stderr
index fdbbc53e4df..c25c804df75 100644
--- a/src/tools/clippy/tests/ui/manual_retain.stderr
+++ b/src/tools/clippy/tests/ui/manual_retain.stderr
@@ -1,5 +1,5 @@
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:27:5
+  --> tests/ui/manual_retain.rs:25:5
    |
 LL |     binary_heap = binary_heap.into_iter().filter(|x| x % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `binary_heap.retain(|x| x % 2 == 0)`
@@ -8,43 +8,43 @@ LL |     binary_heap = binary_heap.into_iter().filter(|x| x % 2 == 0).collect();
    = help: to override `-D warnings` add `#[allow(clippy::manual_retain)]`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:28:5
+  --> tests/ui/manual_retain.rs:26:5
    |
 LL |     binary_heap = binary_heap.iter().filter(|&x| x % 2 == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `binary_heap.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:29:5
+  --> tests/ui/manual_retain.rs:27:5
    |
 LL |     binary_heap = binary_heap.iter().filter(|&x| x % 2 == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `binary_heap.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:33:5
+  --> tests/ui/manual_retain.rs:31:5
    |
 LL |     tuples = tuples.iter().filter(|(ref x, ref y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(ref x, ref y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:34:5
+  --> tests/ui/manual_retain.rs:32:5
    |
 LL |     tuples = tuples.iter().filter(|(x, y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(x, y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:64:5
+  --> tests/ui/manual_retain.rs:62:5
    |
 LL |     btree_map = btree_map.into_iter().filter(|(k, _)| k % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `btree_map.retain(|k, _| k % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:65:5
+  --> tests/ui/manual_retain.rs:63:5
    |
 LL |     btree_map = btree_map.into_iter().filter(|(_, v)| v % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `btree_map.retain(|_, &mut v| v % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:66:5
+  --> tests/ui/manual_retain.rs:64:5
    |
 LL | /     btree_map = btree_map
 LL | |         .into_iter()
@@ -53,49 +53,49 @@ LL | |         .collect();
    | |__________________^ help: consider calling `.retain()` instead: `btree_map.retain(|k, &mut v| (k % 2 == 0) && (v % 2 == 0))`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:91:5
+  --> tests/ui/manual_retain.rs:89:5
    |
 LL |     btree_set = btree_set.iter().filter(|&x| x % 2 == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `btree_set.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:92:5
+  --> tests/ui/manual_retain.rs:90:5
    |
 LL |     btree_set = btree_set.iter().filter(|&x| x % 2 == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `btree_set.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:93:5
+  --> tests/ui/manual_retain.rs:91:5
    |
 LL |     btree_set = btree_set.into_iter().filter(|x| x % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `btree_set.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:97:5
+  --> tests/ui/manual_retain.rs:95:5
    |
 LL |     tuples = tuples.iter().filter(|(ref x, ref y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(ref x, ref y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:98:5
+  --> tests/ui/manual_retain.rs:96:5
    |
 LL |     tuples = tuples.iter().filter(|(x, y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(x, y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:128:5
+  --> tests/ui/manual_retain.rs:126:5
    |
 LL |     hash_map = hash_map.into_iter().filter(|(k, _)| k % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `hash_map.retain(|k, _| k % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:129:5
+  --> tests/ui/manual_retain.rs:127:5
    |
 LL |     hash_map = hash_map.into_iter().filter(|(_, v)| v % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `hash_map.retain(|_, &mut v| v % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:130:5
+  --> tests/ui/manual_retain.rs:128:5
    |
 LL | /     hash_map = hash_map
 LL | |         .into_iter()
@@ -104,133 +104,133 @@ LL | |         .collect();
    | |__________________^ help: consider calling `.retain()` instead: `hash_map.retain(|k, &mut v| (k % 2 == 0) && (v % 2 == 0))`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:154:5
+  --> tests/ui/manual_retain.rs:152:5
    |
 LL |     hash_set = hash_set.into_iter().filter(|x| x % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `hash_set.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:155:5
+  --> tests/ui/manual_retain.rs:153:5
    |
 LL |     hash_set = hash_set.iter().filter(|&x| x % 2 == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `hash_set.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:156:5
+  --> tests/ui/manual_retain.rs:154:5
    |
 LL |     hash_set = hash_set.iter().filter(|&x| x % 2 == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `hash_set.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:160:5
+  --> tests/ui/manual_retain.rs:158:5
    |
 LL |     tuples = tuples.iter().filter(|(ref x, ref y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(ref x, ref y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:161:5
+  --> tests/ui/manual_retain.rs:159:5
    |
 LL |     tuples = tuples.iter().filter(|(x, y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(x, y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:190:5
+  --> tests/ui/manual_retain.rs:188:5
    |
 LL |     s = s.chars().filter(|&c| c != 'o').to_owned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `s.retain(|c| c != 'o')`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:202:5
+  --> tests/ui/manual_retain.rs:200:5
    |
 LL |     vec = vec.iter().filter(|&x| x % 2 == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:203:5
+  --> tests/ui/manual_retain.rs:201:5
    |
 LL |     vec = vec.iter().filter(|&x| x % 2 == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:204:5
+  --> tests/ui/manual_retain.rs:202:5
    |
 LL |     vec = vec.into_iter().filter(|x| x % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:208:5
+  --> tests/ui/manual_retain.rs:206:5
    |
 LL |     tuples = tuples.iter().filter(|(ref x, ref y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(ref x, ref y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:209:5
+  --> tests/ui/manual_retain.rs:207:5
    |
 LL |     tuples = tuples.iter().filter(|(x, y)| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(x, y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:231:5
+  --> tests/ui/manual_retain.rs:229:5
    |
 LL |     vec_deque = vec_deque.iter().filter(|&x| x % 2 == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec_deque.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:232:5
+  --> tests/ui/manual_retain.rs:230:5
    |
 LL |     vec_deque = vec_deque.iter().filter(|&x| x % 2 == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec_deque.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:233:5
+  --> tests/ui/manual_retain.rs:231:5
    |
 LL |     vec_deque = vec_deque.into_iter().filter(|x| x % 2 == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec_deque.retain(|x| x % 2 == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:290:5
+  --> tests/ui/manual_retain.rs:288:5
    |
 LL |     vec = vec.into_iter().filter(|(x, y)| *x == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|(x, y)| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:294:5
+  --> tests/ui/manual_retain.rs:292:5
    |
 LL |     tuples = tuples.into_iter().filter(|(_, n)| *n > 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `tuples.retain(|(_, n)| *n > 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:311:5
+  --> tests/ui/manual_retain.rs:309:5
    |
 LL |     vec = vec.iter().filter(|&&x| x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|&x| x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:312:5
+  --> tests/ui/manual_retain.rs:310:5
    |
 LL |     vec = vec.iter().filter(|&&x| x == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|&x| x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:313:5
+  --> tests/ui/manual_retain.rs:311:5
    |
 LL |     vec = vec.into_iter().filter(|&x| x == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|&x| x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:316:5
+  --> tests/ui/manual_retain.rs:314:5
    |
 LL |     vec = vec.iter().filter(|&x| *x == 0).copied().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|x| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:317:5
+  --> tests/ui/manual_retain.rs:315:5
    |
 LL |     vec = vec.iter().filter(|&x| *x == 0).cloned().collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|x| *x == 0)`
 
 error: this expression can be written more simply using `.retain()`
-  --> tests/ui/manual_retain.rs:318:5
+  --> tests/ui/manual_retain.rs:316:5
    |
 LL |     vec = vec.into_iter().filter(|x| *x == 0).collect();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `.retain()` instead: `vec.retain(|x| *x == 0)`
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or.fixed b/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
index 737d4c90dca..dffd44b6a7c 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.fixed
@@ -1,5 +1,10 @@
 #![allow(dead_code)]
-#![allow(unused_variables, clippy::unnecessary_wraps, clippy::unnecessary_literal_unwrap)]
+#![allow(
+    unused_variables,
+    clippy::unnecessary_wraps,
+    clippy::unnecessary_literal_unwrap,
+    clippy::manual_unwrap_or_default
+)]
 
 fn option_unwrap_or() {
     // int case
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or.rs b/src/tools/clippy/tests/ui/manual_unwrap_or.rs
index f59fb87529f..67427132c1a 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.rs
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.rs
@@ -1,5 +1,10 @@
 #![allow(dead_code)]
-#![allow(unused_variables, clippy::unnecessary_wraps, clippy::unnecessary_literal_unwrap)]
+#![allow(
+    unused_variables,
+    clippy::unnecessary_wraps,
+    clippy::unnecessary_literal_unwrap,
+    clippy::manual_unwrap_or_default
+)]
 
 fn option_unwrap_or() {
     // int case
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or.stderr b/src/tools/clippy/tests/ui/manual_unwrap_or.stderr
index 511b79881ac..33a099680ce 100644
--- a/src/tools/clippy/tests/ui/manual_unwrap_or.stderr
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or.stderr
@@ -1,5 +1,5 @@
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:6:5
+  --> tests/ui/manual_unwrap_or.rs:11:5
    |
 LL | /     match Some(1) {
 LL | |         Some(i) => i,
@@ -11,7 +11,7 @@ LL | |     };
    = help: to override `-D warnings` add `#[allow(clippy::manual_unwrap_or)]`
 
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:12:5
+  --> tests/ui/manual_unwrap_or.rs:17:5
    |
 LL | /     match Some(1) {
 LL | |         None => 42,
@@ -20,7 +20,7 @@ LL | |     };
    | |_____^ help: replace with: `Some(1).unwrap_or(42)`
 
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:18:5
+  --> tests/ui/manual_unwrap_or.rs:23:5
    |
 LL | /     match Some(1) {
 LL | |         Some(i) => i,
@@ -29,7 +29,7 @@ LL | |     };
    | |_____^ help: replace with: `Some(1).unwrap_or(1 + 42)`
 
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:25:5
+  --> tests/ui/manual_unwrap_or.rs:30:5
    |
 LL | /     match Some(1) {
 LL | |         Some(i) => i,
@@ -50,7 +50,7 @@ LL ~     });
    |
 
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:35:5
+  --> tests/ui/manual_unwrap_or.rs:40:5
    |
 LL | /     match Some("Bob") {
 LL | |         Some(i) => i,
@@ -59,7 +59,7 @@ LL | |     };
    | |_____^ help: replace with: `Some("Bob").unwrap_or("Alice")`
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:85:5
+  --> tests/ui/manual_unwrap_or.rs:90:5
    |
 LL | /     match Ok::<i32, &str>(1) {
 LL | |         Ok(i) => i,
@@ -68,7 +68,7 @@ LL | |     };
    | |_____^ help: replace with: `Ok::<i32, &str>(1).unwrap_or(42)`
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:92:5
+  --> tests/ui/manual_unwrap_or.rs:97:5
    |
 LL | /     match a {
 LL | |         Ok(i) => i,
@@ -77,7 +77,7 @@ LL | |     };
    | |_____^ help: replace with: `a.unwrap_or(42)`
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:98:5
+  --> tests/ui/manual_unwrap_or.rs:103:5
    |
 LL | /     match Ok(1) as Result<i32, &str> {
 LL | |         Ok(i) => i,
@@ -86,7 +86,7 @@ LL | |     };
    | |_____^ help: replace with: `(Ok(1) as Result<i32, &str>).unwrap_or(42)`
 
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:111:5
+  --> tests/ui/manual_unwrap_or.rs:116:5
    |
 LL | /     match s.method() {
 LL | |         Some(i) => i,
@@ -95,7 +95,7 @@ LL | |     };
    | |_____^ help: replace with: `s.method().unwrap_or(42)`
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:117:5
+  --> tests/ui/manual_unwrap_or.rs:122:5
    |
 LL | /     match Ok::<i32, &str>(1) {
 LL | |         Err(_) => 42,
@@ -104,7 +104,7 @@ LL | |     };
    | |_____^ help: replace with: `Ok::<i32, &str>(1).unwrap_or(42)`
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:123:5
+  --> tests/ui/manual_unwrap_or.rs:128:5
    |
 LL | /     match Ok::<i32, &str>(1) {
 LL | |         Ok(i) => i,
@@ -113,7 +113,7 @@ LL | |     };
    | |_____^ help: replace with: `Ok::<i32, &str>(1).unwrap_or(1 + 42)`
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:130:5
+  --> tests/ui/manual_unwrap_or.rs:135:5
    |
 LL | /     match Ok::<i32, &str>(1) {
 LL | |         Ok(i) => i,
@@ -134,7 +134,7 @@ LL ~     });
    |
 
 error: this pattern reimplements `Result::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:140:5
+  --> tests/ui/manual_unwrap_or.rs:145:5
    |
 LL | /     match Ok::<&str, &str>("Bob") {
 LL | |         Ok(i) => i,
@@ -143,7 +143,7 @@ LL | |     };
    | |_____^ help: replace with: `Ok::<&str, &str>("Bob").unwrap_or("Alice")`
 
 error: this pattern reimplements `Option::unwrap_or`
-  --> tests/ui/manual_unwrap_or.rs:200:17
+  --> tests/ui/manual_unwrap_or.rs:205:17
    |
 LL |           let _ = match some_macro!() {
    |  _________________^
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or_default.fixed b/src/tools/clippy/tests/ui/manual_unwrap_or_default.fixed
new file mode 100644
index 00000000000..c8456805ee6
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or_default.fixed
@@ -0,0 +1,19 @@
+#![warn(clippy::manual_unwrap_or_default)]
+#![allow(clippy::unnecessary_literal_unwrap)]
+
+fn main() {
+    let x: Option<Vec<String>> = None;
+    x.unwrap_or_default();
+
+    let x: Option<Vec<String>> = None;
+    x.unwrap_or_default();
+
+    let x: Option<String> = None;
+    x.unwrap_or_default();
+
+    let x: Option<Vec<String>> = None;
+    x.unwrap_or_default();
+
+    let x: Option<Vec<String>> = None;
+    x.unwrap_or_default();
+}
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or_default.rs b/src/tools/clippy/tests/ui/manual_unwrap_or_default.rs
new file mode 100644
index 00000000000..820717be53a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or_default.rs
@@ -0,0 +1,40 @@
+#![warn(clippy::manual_unwrap_or_default)]
+#![allow(clippy::unnecessary_literal_unwrap)]
+
+fn main() {
+    let x: Option<Vec<String>> = None;
+    match x {
+        //~^ ERROR: match can be simplified with `.unwrap_or_default()`
+        Some(v) => v,
+        None => Vec::default(),
+    };
+
+    let x: Option<Vec<String>> = None;
+    match x {
+        //~^ ERROR: match can be simplified with `.unwrap_or_default()`
+        Some(v) => v,
+        _ => Vec::default(),
+    };
+
+    let x: Option<String> = None;
+    match x {
+        //~^ ERROR: match can be simplified with `.unwrap_or_default()`
+        Some(v) => v,
+        None => String::new(),
+    };
+
+    let x: Option<Vec<String>> = None;
+    match x {
+        //~^ ERROR: match can be simplified with `.unwrap_or_default()`
+        None => Vec::default(),
+        Some(v) => v,
+    };
+
+    let x: Option<Vec<String>> = None;
+    if let Some(v) = x {
+        //~^ ERROR: if let can be simplified with `.unwrap_or_default()`
+        v
+    } else {
+        Vec::default()
+    };
+}
diff --git a/src/tools/clippy/tests/ui/manual_unwrap_or_default.stderr b/src/tools/clippy/tests/ui/manual_unwrap_or_default.stderr
new file mode 100644
index 00000000000..f4eb6583588
--- /dev/null
+++ b/src/tools/clippy/tests/ui/manual_unwrap_or_default.stderr
@@ -0,0 +1,56 @@
+error: match can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:6:5
+   |
+LL | /     match x {
+LL | |
+LL | |         Some(v) => v,
+LL | |         None => Vec::default(),
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+   |
+   = note: `-D clippy::manual-unwrap-or-default` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::manual_unwrap_or_default)]`
+
+error: match can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:13:5
+   |
+LL | /     match x {
+LL | |
+LL | |         Some(v) => v,
+LL | |         _ => Vec::default(),
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+
+error: match can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:20:5
+   |
+LL | /     match x {
+LL | |
+LL | |         Some(v) => v,
+LL | |         None => String::new(),
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+
+error: match can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:27:5
+   |
+LL | /     match x {
+LL | |
+LL | |         None => Vec::default(),
+LL | |         Some(v) => v,
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+
+error: if let can be simplified with `.unwrap_or_default()`
+  --> tests/ui/manual_unwrap_or_default.rs:34:5
+   |
+LL | /     if let Some(v) = x {
+LL | |
+LL | |         v
+LL | |     } else {
+LL | |         Vec::default()
+LL | |     };
+   | |_____^ help: replace it with: `x.unwrap_or_default()`
+
+error: aborting due to 5 previous errors
+
diff --git a/src/tools/clippy/tests/ui/map_clone.fixed b/src/tools/clippy/tests/ui/map_clone.fixed
index 395eea69294..e58b6b2f19e 100644
--- a/src/tools/clippy/tests/ui/map_clone.fixed
+++ b/src/tools/clippy/tests/ui/map_clone.fixed
@@ -6,7 +6,8 @@
     clippy::redundant_clone,
     clippy::redundant_closure,
     clippy::useless_asref,
-    clippy::useless_vec
+    clippy::useless_vec,
+    clippy::empty_loop
 )]
 
 fn main() {
@@ -117,4 +118,17 @@ fn main() {
     let y = x.as_ref().map(|x| String::clone(x));
     let x: Result<String, ()> = Ok(String::new());
     let y = x.as_ref().map(|x| String::clone(x));
+
+    // Issue #12271
+    {
+        // Don't lint these
+        let x: Option<&u8> = None;
+        let y = x.map(|x| String::clone(loop {}));
+        let x: Option<&u8> = None;
+        let y = x.map(|x| u8::clone(loop {}));
+        let x: Vec<&u8> = vec![];
+        let y = x.into_iter().map(|x| String::clone(loop {}));
+        let x: Vec<&u8> = vec![];
+        let y = x.into_iter().map(|x| u8::clone(loop {}));
+    }
 }
diff --git a/src/tools/clippy/tests/ui/map_clone.rs b/src/tools/clippy/tests/ui/map_clone.rs
index 82a103edf5a..e642e4046f8 100644
--- a/src/tools/clippy/tests/ui/map_clone.rs
+++ b/src/tools/clippy/tests/ui/map_clone.rs
@@ -6,7 +6,8 @@
     clippy::redundant_clone,
     clippy::redundant_closure,
     clippy::useless_asref,
-    clippy::useless_vec
+    clippy::useless_vec,
+    clippy::empty_loop
 )]
 
 fn main() {
@@ -117,4 +118,17 @@ fn main() {
     let y = x.as_ref().map(|x| String::clone(x));
     let x: Result<String, ()> = Ok(String::new());
     let y = x.as_ref().map(|x| String::clone(x));
+
+    // Issue #12271
+    {
+        // Don't lint these
+        let x: Option<&u8> = None;
+        let y = x.map(|x| String::clone(loop {}));
+        let x: Option<&u8> = None;
+        let y = x.map(|x| u8::clone(loop {}));
+        let x: Vec<&u8> = vec![];
+        let y = x.into_iter().map(|x| String::clone(loop {}));
+        let x: Vec<&u8> = vec![];
+        let y = x.into_iter().map(|x| u8::clone(loop {}));
+    }
 }
diff --git a/src/tools/clippy/tests/ui/map_clone.stderr b/src/tools/clippy/tests/ui/map_clone.stderr
index 1a26a26a4ca..d9e025de4ab 100644
--- a/src/tools/clippy/tests/ui/map_clone.stderr
+++ b/src/tools/clippy/tests/ui/map_clone.stderr
@@ -1,5 +1,5 @@
 error: you are using an explicit closure for copying elements
-  --> tests/ui/map_clone.rs:13:22
+  --> tests/ui/map_clone.rs:14:22
    |
 LL |     let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `vec![5_i8; 6].iter().copied()`
@@ -8,85 +8,85 @@ LL |     let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
    = help: to override `-D warnings` add `#[allow(clippy::map_clone)]`
 
 error: you are using an explicit closure for cloning elements
-  --> tests/ui/map_clone.rs:14:26
+  --> tests/ui/map_clone.rs:15:26
    |
 LL |     let _: Vec<String> = vec![String::new()].iter().map(|x| x.clone()).collect();
    |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `vec![String::new()].iter().cloned()`
 
 error: you are using an explicit closure for copying elements
-  --> tests/ui/map_clone.rs:15:23
+  --> tests/ui/map_clone.rs:16:23
    |
 LL |     let _: Vec<u32> = vec![42, 43].iter().map(|&x| x).collect();
    |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `vec![42, 43].iter().copied()`
 
 error: you are using an explicit closure for copying elements
-  --> tests/ui/map_clone.rs:17:26
+  --> tests/ui/map_clone.rs:18:26
    |
 LL |     let _: Option<u64> = Some(&16).map(|b| *b);
    |                          ^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `Some(&16).copied()`
 
 error: you are using an explicit closure for copying elements
-  --> tests/ui/map_clone.rs:18:25
+  --> tests/ui/map_clone.rs:19:25
    |
 LL |     let _: Option<u8> = Some(&1).map(|x| x.clone());
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `Some(&1).copied()`
 
 error: you are needlessly cloning iterator elements
-  --> tests/ui/map_clone.rs:29:29
+  --> tests/ui/map_clone.rs:30:29
    |
 LL |     let _ = std::env::args().map(|v| v.clone());
    |                             ^^^^^^^^^^^^^^^^^^^ help: remove the `map` call
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:68:13
+  --> tests/ui/map_clone.rs:69:13
    |
 LL |     let y = x.map(|x| String::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:70:13
+  --> tests/ui/map_clone.rs:71:13
    |
 LL |     let y = x.map(Clone::clone);
    |             ^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:73:13
+  --> tests/ui/map_clone.rs:74:13
    |
 LL |     let y = x.map(String::clone);
    |             ^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:79:13
+  --> tests/ui/map_clone.rs:80:13
    |
 LL |     let y = x.map(|x| u32::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:82:13
+  --> tests/ui/map_clone.rs:83:13
    |
 LL |     let y = x.map(|x| Clone::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:94:13
+  --> tests/ui/map_clone.rs:95:13
    |
 LL |     let y = x.map(|x| String::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:97:13
+  --> tests/ui/map_clone.rs:98:13
    |
 LL |     let y = x.map(|x| Clone::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `x.cloned()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:103:13
+  --> tests/ui/map_clone.rs:104:13
    |
 LL |     let y = x.map(|x| u32::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
 
 error: you are explicitly cloning with `.map()`
-  --> tests/ui/map_clone.rs:106:13
+  --> tests/ui/map_clone.rs:107:13
    |
 LL |     let y = x.map(|x| Clone::clone(x));
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `copied` method: `x.copied()`
diff --git a/src/tools/clippy/tests/ui/match_result_ok.fixed b/src/tools/clippy/tests/ui/match_result_ok.fixed
index 8d7cddc0ad7..76b26f5e438 100644
--- a/src/tools/clippy/tests/ui/match_result_ok.fixed
+++ b/src/tools/clippy/tests/ui/match_result_ok.fixed
@@ -1,6 +1,6 @@
 #![warn(clippy::match_result_ok)]
 #![allow(dead_code)]
-#![allow(clippy::boxed_local, clippy::uninlined_format_args)]
+#![allow(clippy::boxed_local, clippy::uninlined_format_args, clippy::manual_unwrap_or_default)]
 
 // Checking `if` cases
 
diff --git a/src/tools/clippy/tests/ui/match_result_ok.rs b/src/tools/clippy/tests/ui/match_result_ok.rs
index 9a18b813aca..d6f2475ba79 100644
--- a/src/tools/clippy/tests/ui/match_result_ok.rs
+++ b/src/tools/clippy/tests/ui/match_result_ok.rs
@@ -1,6 +1,6 @@
 #![warn(clippy::match_result_ok)]
 #![allow(dead_code)]
-#![allow(clippy::boxed_local, clippy::uninlined_format_args)]
+#![allow(clippy::boxed_local, clippy::uninlined_format_args, clippy::manual_unwrap_or_default)]
 
 // Checking `if` cases
 
diff --git a/src/tools/clippy/tests/ui/missing_doc.rs b/src/tools/clippy/tests/ui/missing_doc.rs
index 9bfad3b96cf..9c936d7fa23 100644
--- a/src/tools/clippy/tests/ui/missing_doc.rs
+++ b/src/tools/clippy/tests/ui/missing_doc.rs
@@ -1,5 +1,6 @@
 //@needs-asm-support
 //@aux-build: proc_macros.rs
+//@aux-build: proc_macro_attr.rs
 
 #![warn(clippy::missing_docs_in_private_items)]
 // When denying at the crate level, be sure to not get random warnings from the
@@ -8,6 +9,8 @@
 //! Some garbage docs for the crate here
 #![doc = "More garbage"]
 
+#[macro_use]
+extern crate proc_macro_attr;
 extern crate proc_macros;
 
 use proc_macros::with_span;
@@ -112,3 +115,12 @@ with_span!(span pub enum FooPm3 { A, B(u32), C { field: u32 }});
 with_span!(span pub fn foo_pm() {});
 with_span!(span pub static FOO_PM: u32 = 0;);
 with_span!(span pub const FOO2_PM: u32 = 0;);
+
+// issue #12197
+// Undocumented field originated inside of spanned proc-macro attribute
+/// Some dox for struct.
+#[rewrite_struct]
+pub struct Test {
+    /// Dox
+    a: u8,
+}
diff --git a/src/tools/clippy/tests/ui/missing_doc.stderr b/src/tools/clippy/tests/ui/missing_doc.stderr
index 7e66e2097e9..ef0f96a5b71 100644
--- a/src/tools/clippy/tests/ui/missing_doc.stderr
+++ b/src/tools/clippy/tests/ui/missing_doc.stderr
@@ -1,5 +1,5 @@
 error: missing documentation for a type alias
-  --> tests/ui/missing_doc.rs:16:1
+  --> tests/ui/missing_doc.rs:19:1
    |
 LL | type Typedef = String;
    | ^^^^^^^^^^^^^^^^^^^^^^
@@ -8,19 +8,19 @@ LL | type Typedef = String;
    = help: to override `-D warnings` add `#[allow(clippy::missing_docs_in_private_items)]`
 
 error: missing documentation for a module
-  --> tests/ui/missing_doc.rs:19:1
+  --> tests/ui/missing_doc.rs:22:1
    |
 LL | mod module_no_dox {}
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> tests/ui/missing_doc.rs:25:1
+  --> tests/ui/missing_doc.rs:28:1
    |
 LL | fn foo3() {}
    | ^^^^^^^^^^^^
 
 error: missing documentation for an enum
-  --> tests/ui/missing_doc.rs:39:1
+  --> tests/ui/missing_doc.rs:42:1
    |
 LL | / enum Baz {
 LL | |     BazA { a: isize, b: isize },
@@ -29,43 +29,43 @@ LL | | }
    | |_^
 
 error: missing documentation for a variant
-  --> tests/ui/missing_doc.rs:40:5
+  --> tests/ui/missing_doc.rs:43:5
    |
 LL |     BazA { a: isize, b: isize },
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a struct field
-  --> tests/ui/missing_doc.rs:40:12
+  --> tests/ui/missing_doc.rs:43:12
    |
 LL |     BazA { a: isize, b: isize },
    |            ^^^^^^^^
 
 error: missing documentation for a struct field
-  --> tests/ui/missing_doc.rs:40:22
+  --> tests/ui/missing_doc.rs:43:22
    |
 LL |     BazA { a: isize, b: isize },
    |                      ^^^^^^^^
 
 error: missing documentation for a variant
-  --> tests/ui/missing_doc.rs:41:5
+  --> tests/ui/missing_doc.rs:44:5
    |
 LL |     BarB,
    |     ^^^^
 
 error: missing documentation for a constant
-  --> tests/ui/missing_doc.rs:65:1
+  --> tests/ui/missing_doc.rs:68:1
    |
 LL | const FOO: u32 = 0;
    | ^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a static
-  --> tests/ui/missing_doc.rs:74:1
+  --> tests/ui/missing_doc.rs:77:1
    |
 LL | static BAR: u32 = 0;
    | ^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a module
-  --> tests/ui/missing_doc.rs:83:1
+  --> tests/ui/missing_doc.rs:86:1
    |
 LL | / mod internal_impl {
 LL | |     /// dox
@@ -77,13 +77,13 @@ LL | | }
    | |_^
 
 error: missing documentation for a function
-  --> tests/ui/missing_doc.rs:88:5
+  --> tests/ui/missing_doc.rs:91:5
    |
 LL |     fn undocumented3() {}
    |     ^^^^^^^^^^^^^^^^^^^^^
 
 error: missing documentation for a function
-  --> tests/ui/missing_doc.rs:94:9
+  --> tests/ui/missing_doc.rs:97:9
    |
 LL |         fn also_undocumented2() {}
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/mixed_attributes_style.rs b/src/tools/clippy/tests/ui/mixed_attributes_style.rs
index ad93e3019fa..4f89aa8a5e5 100644
--- a/src/tools/clippy/tests/ui/mixed_attributes_style.rs
+++ b/src/tools/clippy/tests/ui/mixed_attributes_style.rs
@@ -1,4 +1,5 @@
 #![warn(clippy::mixed_attributes_style)]
+#![allow(clippy::duplicated_attributes)]
 
 #[allow(unused)] //~ ERROR: item has both inner and outer attributes
 fn foo1() {
diff --git a/src/tools/clippy/tests/ui/mixed_attributes_style.stderr b/src/tools/clippy/tests/ui/mixed_attributes_style.stderr
index d1d5cd3f47f..ed798073cb7 100644
--- a/src/tools/clippy/tests/ui/mixed_attributes_style.stderr
+++ b/src/tools/clippy/tests/ui/mixed_attributes_style.stderr
@@ -1,5 +1,5 @@
 error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style.rs:3:1
+  --> tests/ui/mixed_attributes_style.rs:4:1
    |
 LL | / #[allow(unused)]
 LL | | fn foo1() {
@@ -10,7 +10,7 @@ LL | |     #![allow(unused)]
    = help: to override `-D warnings` add `#[allow(clippy::mixed_attributes_style)]`
 
 error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style.rs:17:1
+  --> tests/ui/mixed_attributes_style.rs:18:1
    |
 LL | / /// linux
 LL | |
@@ -19,7 +19,7 @@ LL | |     //! windows
    | |_______________^
 
 error: item has both inner and outer attributes
-  --> tests/ui/mixed_attributes_style.rs:32:1
+  --> tests/ui/mixed_attributes_style.rs:33:1
    |
 LL | / #[allow(unused)]
 LL | | mod bar {
diff --git a/src/tools/clippy/tests/ui/mut_mut.rs b/src/tools/clippy/tests/ui/mut_mut.rs
index 288b003405d..4c45bc98026 100644
--- a/src/tools/clippy/tests/ui/mut_mut.rs
+++ b/src/tools/clippy/tests/ui/mut_mut.rs
@@ -1,5 +1,4 @@
 //@aux-build:proc_macros.rs
-//@compile-flags: -Zdeduplicate-diagnostics=yes
 
 #![warn(clippy::mut_mut)]
 #![allow(unused)]
@@ -82,3 +81,8 @@ mod issue9035 {
 
     fn bar(_: &mut impl Display) {}
 }
+
+fn allow_works() {
+    #[allow(clippy::mut_mut)]
+    let _ = &mut &mut 1;
+}
diff --git a/src/tools/clippy/tests/ui/mut_mut.stderr b/src/tools/clippy/tests/ui/mut_mut.stderr
index 73f2410a252..42853fdc008 100644
--- a/src/tools/clippy/tests/ui/mut_mut.stderr
+++ b/src/tools/clippy/tests/ui/mut_mut.stderr
@@ -1,5 +1,5 @@
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:16:11
+  --> tests/ui/mut_mut.rs:15:11
    |
 LL | fn fun(x: &mut &mut u32) -> bool {
    |           ^^^^^^^^^^^^^
@@ -8,13 +8,13 @@ LL | fn fun(x: &mut &mut u32) -> bool {
    = help: to override `-D warnings` add `#[allow(clippy::mut_mut)]`
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:33:17
+  --> tests/ui/mut_mut.rs:32:17
    |
 LL |     let mut x = &mut &mut 1u32;
    |                 ^^^^^^^^^^^^^^
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:48:25
+  --> tests/ui/mut_mut.rs:47:25
    |
 LL |     let mut z = inline!(&mut $(&mut 3u32));
    |                         ^
@@ -22,37 +22,37 @@ LL |     let mut z = inline!(&mut $(&mut 3u32));
    = note: this error originates in the macro `__inline_mac_fn_main` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: this expression mutably borrows a mutable reference. Consider reborrowing
-  --> tests/ui/mut_mut.rs:35:21
+  --> tests/ui/mut_mut.rs:34:21
    |
 LL |         let mut y = &mut x;
    |                     ^^^^^^
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:39:32
+  --> tests/ui/mut_mut.rs:38:32
    |
 LL |         let y: &mut &mut u32 = &mut &mut 2;
    |                                ^^^^^^^^^^^
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:39:16
+  --> tests/ui/mut_mut.rs:38:16
    |
 LL |         let y: &mut &mut u32 = &mut &mut 2;
    |                ^^^^^^^^^^^^^
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:44:37
+  --> tests/ui/mut_mut.rs:43:37
    |
 LL |         let y: &mut &mut &mut u32 = &mut &mut &mut 2;
    |                                     ^^^^^^^^^^^^^^^^
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:44:16
+  --> tests/ui/mut_mut.rs:43:16
    |
 LL |         let y: &mut &mut &mut u32 = &mut &mut &mut 2;
    |                ^^^^^^^^^^^^^^^^^^
 
 error: generally you want to avoid `&mut &mut _` if possible
-  --> tests/ui/mut_mut.rs:44:21
+  --> tests/ui/mut_mut.rs:43:21
    |
 LL |         let y: &mut &mut &mut u32 = &mut &mut &mut 2;
    |                     ^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed b/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed
index 201f8a4c19d..a8176618c1f 100644
--- a/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed
+++ b/src/tools/clippy/tests/ui/needless_bitwise_bool.fixed
@@ -1,4 +1,5 @@
 #![warn(clippy::needless_bitwise_bool)]
+#![allow(clippy::const_is_empty)]
 
 fn returns_bool() -> bool {
     true
diff --git a/src/tools/clippy/tests/ui/needless_bitwise_bool.rs b/src/tools/clippy/tests/ui/needless_bitwise_bool.rs
index b0e5014b74b..f190eb2b76e 100644
--- a/src/tools/clippy/tests/ui/needless_bitwise_bool.rs
+++ b/src/tools/clippy/tests/ui/needless_bitwise_bool.rs
@@ -1,4 +1,5 @@
 #![warn(clippy::needless_bitwise_bool)]
+#![allow(clippy::const_is_empty)]
 
 fn returns_bool() -> bool {
     true
diff --git a/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr b/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr
index f29d4492540..9f14646c3e5 100644
--- a/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr
+++ b/src/tools/clippy/tests/ui/needless_bitwise_bool.stderr
@@ -1,5 +1,5 @@
 error: use of bitwise operator instead of lazy operator between booleans
-  --> tests/ui/needless_bitwise_bool.rs:22:8
+  --> tests/ui/needless_bitwise_bool.rs:23:8
    |
 LL |     if y & !x {
    |        ^^^^^^ help: try: `y && !x`
diff --git a/src/tools/clippy/tests/ui/needless_return.fixed b/src/tools/clippy/tests/ui/needless_return.fixed
index f9eb39d4938..2575f2449e1 100644
--- a/src/tools/clippy/tests/ui/needless_return.fixed
+++ b/src/tools/clippy/tests/ui/needless_return.fixed
@@ -316,4 +316,11 @@ fn test_match_as_stmt() {
     };
 }
 
+fn allow_works() -> i32 {
+    #[allow(clippy::needless_return, clippy::match_single_binding)]
+    match () {
+        () => return 42,
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/needless_return.rs b/src/tools/clippy/tests/ui/needless_return.rs
index 4dd2e22ea9f..04f21834d88 100644
--- a/src/tools/clippy/tests/ui/needless_return.rs
+++ b/src/tools/clippy/tests/ui/needless_return.rs
@@ -326,4 +326,11 @@ fn test_match_as_stmt() {
     };
 }
 
+fn allow_works() -> i32 {
+    #[allow(clippy::needless_return, clippy::match_single_binding)]
+    match () {
+        () => return 42,
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/no_effect_replace.rs b/src/tools/clippy/tests/ui/no_effect_replace.rs
index 2a940d87fb9..e4fd5caae2a 100644
--- a/src/tools/clippy/tests/ui/no_effect_replace.rs
+++ b/src/tools/clippy/tests/ui/no_effect_replace.rs
@@ -1,5 +1,3 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::no_effect_replace)]
 
 fn main() {
diff --git a/src/tools/clippy/tests/ui/no_effect_replace.stderr b/src/tools/clippy/tests/ui/no_effect_replace.stderr
index ad2dcd2cc9b..ded86c5c5b8 100644
--- a/src/tools/clippy/tests/ui/no_effect_replace.stderr
+++ b/src/tools/clippy/tests/ui/no_effect_replace.stderr
@@ -1,5 +1,5 @@
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:6:13
+  --> tests/ui/no_effect_replace.rs:4:13
    |
 LL |     let _ = "12345".replace('1', "1");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -8,43 +8,43 @@ LL |     let _ = "12345".replace('1', "1");
    = help: to override `-D warnings` add `#[allow(clippy::no_effect_replace)]`
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:9:13
+  --> tests/ui/no_effect_replace.rs:7:13
    |
 LL |     let _ = "12345".replace("12", "12");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:11:13
+  --> tests/ui/no_effect_replace.rs:9:13
    |
 LL |     let _ = String::new().replace("12", "12");
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:14:13
+  --> tests/ui/no_effect_replace.rs:12:13
    |
 LL |     let _ = "12345".replacen('1', "1", 1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:16:13
+  --> tests/ui/no_effect_replace.rs:14:13
    |
 LL |     let _ = "12345".replacen("12", "12", 1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:18:13
+  --> tests/ui/no_effect_replace.rs:16:13
    |
 LL |     let _ = String::new().replacen("12", "12", 1);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:25:13
+  --> tests/ui/no_effect_replace.rs:23:13
    |
 LL |     let _ = "hello".replace(&x.f(), &x.f());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: replacing text with itself
-  --> tests/ui/no_effect_replace.rs:29:13
+  --> tests/ui/no_effect_replace.rs:27:13
    |
 LL |     let _ = "hello".replace(&y(), &y());
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.fixed b/src/tools/clippy/tests/ui/option_if_let_else.fixed
index d443334bb05..eeab801b7da 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.fixed
+++ b/src/tools/clippy/tests/ui/option_if_let_else.fixed
@@ -3,7 +3,8 @@
     clippy::ref_option_ref,
     clippy::equatable_if_let,
     clippy::let_unit_value,
-    clippy::redundant_locals
+    clippy::redundant_locals,
+    clippy::manual_unwrap_or_default
 )]
 
 fn bad1(string: Option<&str>) -> (bool, &str) {
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.rs b/src/tools/clippy/tests/ui/option_if_let_else.rs
index 317c35bf842..3e5b96d7c31 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.rs
+++ b/src/tools/clippy/tests/ui/option_if_let_else.rs
@@ -3,7 +3,8 @@
     clippy::ref_option_ref,
     clippy::equatable_if_let,
     clippy::let_unit_value,
-    clippy::redundant_locals
+    clippy::redundant_locals,
+    clippy::manual_unwrap_or_default
 )]
 
 fn bad1(string: Option<&str>) -> (bool, &str) {
diff --git a/src/tools/clippy/tests/ui/option_if_let_else.stderr b/src/tools/clippy/tests/ui/option_if_let_else.stderr
index a794dca762f..f5359a0c34f 100644
--- a/src/tools/clippy/tests/ui/option_if_let_else.stderr
+++ b/src/tools/clippy/tests/ui/option_if_let_else.stderr
@@ -1,5 +1,5 @@
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:10:5
+  --> tests/ui/option_if_let_else.rs:11:5
    |
 LL | /     if let Some(x) = string {
 LL | |         (true, x)
@@ -12,19 +12,19 @@ LL | |     }
    = help: to override `-D warnings` add `#[allow(clippy::option_if_let_else)]`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:28:13
+  --> tests/ui/option_if_let_else.rs:29:13
    |
 LL |     let _ = if let Some(s) = *string { s.len() } else { 0 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `string.map_or(0, |s| s.len())`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:29:13
+  --> tests/ui/option_if_let_else.rs:30:13
    |
 LL |     let _ = if let Some(s) = &num { s } else { &0 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `num.as_ref().map_or(&0, |s| s)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:30:13
+  --> tests/ui/option_if_let_else.rs:31:13
    |
 LL |       let _ = if let Some(s) = &mut num {
    |  _____________^
@@ -44,13 +44,13 @@ LL ~     });
    |
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:36:13
+  --> tests/ui/option_if_let_else.rs:37:13
    |
 LL |     let _ = if let Some(ref s) = num { s } else { &0 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `num.as_ref().map_or(&0, |s| s)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:37:13
+  --> tests/ui/option_if_let_else.rs:38:13
    |
 LL |       let _ = if let Some(mut s) = num {
    |  _____________^
@@ -70,7 +70,7 @@ LL ~     });
    |
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:43:13
+  --> tests/ui/option_if_let_else.rs:44:13
    |
 LL |       let _ = if let Some(ref mut s) = num {
    |  _____________^
@@ -90,7 +90,7 @@ LL ~     });
    |
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:52:5
+  --> tests/ui/option_if_let_else.rs:53:5
    |
 LL | /     if let Some(x) = arg {
 LL | |         let y = x * x;
@@ -109,7 +109,7 @@ LL +     })
    |
 
 error: use Option::map_or_else instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:65:13
+  --> tests/ui/option_if_let_else.rs:66:13
    |
 LL |       let _ = if let Some(x) = arg {
    |  _____________^
@@ -121,7 +121,7 @@ LL | |     };
    | |_____^ help: try: `arg.map_or_else(side_effect, |x| x)`
 
 error: use Option::map_or_else instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:74:13
+  --> tests/ui/option_if_let_else.rs:75:13
    |
 LL |       let _ = if let Some(x) = arg {
    |  _____________^
@@ -144,7 +144,7 @@ LL ~     }, |x| x * x * x * x);
    |
 
 error: use Option::map_or_else instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:107:13
+  --> tests/ui/option_if_let_else.rs:108:13
    |
 LL | /             if let Some(idx) = s.find('.') {
 LL | |                 vec![s[..idx].to_string(), s[idx..].to_string()]
@@ -154,7 +154,7 @@ LL | |             }
    | |_____________^ help: try: `s.find('.').map_or_else(|| vec![s.to_string()], |idx| vec![s[..idx].to_string(), s[idx..].to_string()])`
 
 error: use Option::map_or_else instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:118:5
+  --> tests/ui/option_if_let_else.rs:119:5
    |
 LL | /     if let Ok(binding) = variable {
 LL | |         println!("Ok {binding}");
@@ -177,13 +177,13 @@ LL +     })
    |
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:142:13
+  --> tests/ui/option_if_let_else.rs:143:13
    |
 LL |     let _ = if let Some(x) = optional { x + 2 } else { 5 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `optional.map_or(5, |x| x + 2)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:152:13
+  --> tests/ui/option_if_let_else.rs:153:13
    |
 LL |       let _ = if let Some(x) = Some(0) {
    |  _____________^
@@ -205,13 +205,13 @@ LL ~         });
    |
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:180:13
+  --> tests/ui/option_if_let_else.rs:181:13
    |
 LL |     let _ = if let Some(x) = Some(0) { s.len() + x } else { s.len() };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `Some(0).map_or(s.len(), |x| s.len() + x)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:184:13
+  --> tests/ui/option_if_let_else.rs:185:13
    |
 LL |       let _ = if let Some(x) = Some(0) {
    |  _____________^
@@ -231,7 +231,7 @@ LL ~     });
    |
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:223:13
+  --> tests/ui/option_if_let_else.rs:224:13
    |
 LL |       let _ = match s {
    |  _____________^
@@ -241,7 +241,7 @@ LL | |     };
    | |_____^ help: try: `s.map_or(1, |string| string.len())`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:227:13
+  --> tests/ui/option_if_let_else.rs:228:13
    |
 LL |       let _ = match Some(10) {
    |  _____________^
@@ -251,7 +251,7 @@ LL | |     };
    | |_____^ help: try: `Some(10).map_or(5, |a| a + 1)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:233:13
+  --> tests/ui/option_if_let_else.rs:234:13
    |
 LL |       let _ = match res {
    |  _____________^
@@ -261,7 +261,7 @@ LL | |     };
    | |_____^ help: try: `res.map_or(1, |a| a + 1)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:237:13
+  --> tests/ui/option_if_let_else.rs:238:13
    |
 LL |       let _ = match res {
    |  _____________^
@@ -271,13 +271,13 @@ LL | |     };
    | |_____^ help: try: `res.map_or(1, |a| a + 1)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:241:13
+  --> tests/ui/option_if_let_else.rs:242:13
    |
 LL |     let _ = if let Ok(a) = res { a + 1 } else { 5 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `res.map_or(5, |a| a + 1)`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:258:17
+  --> tests/ui/option_if_let_else.rs:259:17
    |
 LL |           let _ = match initial {
    |  _________________^
@@ -287,7 +287,7 @@ LL | |         };
    | |_________^ help: try: `initial.as_ref().map_or(42, |value| do_something(value))`
 
 error: use Option::map_or instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:265:17
+  --> tests/ui/option_if_let_else.rs:266:17
    |
 LL |           let _ = match initial {
    |  _________________^
@@ -297,7 +297,7 @@ LL | |         };
    | |_________^ help: try: `initial.as_mut().map_or(42, |value| do_something2(value))`
 
 error: use Option::map_or_else instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:288:24
+  --> tests/ui/option_if_let_else.rs:289:24
    |
 LL |       let mut _hashmap = if let Some(hm) = &opt {
    |  ________________________^
@@ -308,7 +308,7 @@ LL | |     };
    | |_____^ help: try: `opt.as_ref().map_or_else(HashMap::new, |hm| hm.clone())`
 
 error: use Option::map_or_else instead of an if let/else
-  --> tests/ui/option_if_let_else.rs:294:19
+  --> tests/ui/option_if_let_else.rs:295:19
    |
 LL |     let mut _hm = if let Some(hm) = &opt { hm.clone() } else { new_map!() };
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `opt.as_ref().map_or_else(|| new_map!(), |hm| hm.clone())`
diff --git a/src/tools/clippy/tests/ui/option_option.rs b/src/tools/clippy/tests/ui/option_option.rs
index 2f6e4d76145..42f03aae7bb 100644
--- a/src/tools/clippy/tests/ui/option_option.rs
+++ b/src/tools/clippy/tests/ui/option_option.rs
@@ -1,7 +1,5 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![deny(clippy::option_option)]
-#![allow(clippy::unnecessary_wraps)]
+#![allow(clippy::unnecessary_wraps, clippy::manual_unwrap_or_default)]
 
 const C: Option<Option<i32>> = None;
 //~^ ERROR: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if
diff --git a/src/tools/clippy/tests/ui/option_option.stderr b/src/tools/clippy/tests/ui/option_option.stderr
index 76cb9ae944c..0cd048e400e 100644
--- a/src/tools/clippy/tests/ui/option_option.stderr
+++ b/src/tools/clippy/tests/ui/option_option.stderr
@@ -1,77 +1,77 @@
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:6:10
+  --> tests/ui/option_option.rs:4:10
    |
 LL | const C: Option<Option<i32>> = None;
    |          ^^^^^^^^^^^^^^^^^^^
    |
 note: the lint level is defined here
-  --> tests/ui/option_option.rs:3:9
+  --> tests/ui/option_option.rs:1:9
    |
 LL | #![deny(clippy::option_option)]
    |         ^^^^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:8:11
+  --> tests/ui/option_option.rs:6:11
    |
 LL | static S: Option<Option<i32>> = None;
    |           ^^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:11:13
+  --> tests/ui/option_option.rs:9:13
    |
 LL | fn input(_: Option<Option<u8>>) {}
    |             ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:14:16
+  --> tests/ui/option_option.rs:12:16
    |
 LL | fn output() -> Option<Option<u8>> {
    |                ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:19:27
+  --> tests/ui/option_option.rs:17:27
    |
 LL | fn output_nested() -> Vec<Option<Option<u8>>> {
    |                           ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:25:30
+  --> tests/ui/option_option.rs:23:30
    |
 LL | fn output_nested_nested() -> Option<Option<Option<u8>>> {
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:31:8
+  --> tests/ui/option_option.rs:29:8
    |
 LL |     x: Option<Option<u8>>,
    |        ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:36:23
+  --> tests/ui/option_option.rs:34:23
    |
 LL |     fn struct_fn() -> Option<Option<u8>> {
    |                       ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:43:22
+  --> tests/ui/option_option.rs:41:22
    |
 LL |     fn trait_fn() -> Option<Option<u8>>;
    |                      ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:48:11
+  --> tests/ui/option_option.rs:46:11
    |
 LL |     Tuple(Option<Option<u8>>),
    |           ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:50:17
+  --> tests/ui/option_option.rs:48:17
    |
 LL |     Struct { x: Option<Option<u8>> },
    |                 ^^^^^^^^^^^^^^^^^^
 
 error: consider using `Option<T>` instead of `Option<Option<T>>` or a custom enum if you need to distinguish all 3 cases
-  --> tests/ui/option_option.rs:92:14
+  --> tests/ui/option_option.rs:90:14
    |
 LL |         foo: Option<Option<Cow<'a, str>>>,
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/tools/clippy/tests/ui/read_zero_byte_vec.rs b/src/tools/clippy/tests/ui/read_zero_byte_vec.rs
index fd5a88a37a6..68acf433469 100644
--- a/src/tools/clippy/tests/ui/read_zero_byte_vec.rs
+++ b/src/tools/clippy/tests/ui/read_zero_byte_vec.rs
@@ -112,4 +112,10 @@ async fn test_tokio<R: TokioAsyncRead + Unpin>(r: &mut R) {
     //~^ ERROR: reading zero byte data to `Vec`
 }
 
+fn allow_works<F: std::io::Read>(mut f: F) {
+    let mut data = Vec::with_capacity(100);
+    #[allow(clippy::read_zero_byte_vec)]
+    f.read(&mut data).unwrap();
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/redundant_as_str.fixed b/src/tools/clippy/tests/ui/redundant_as_str.fixed
index 4185b402226..708a1cc9150 100644
--- a/src/tools/clippy/tests/ui/redundant_as_str.fixed
+++ b/src/tools/clippy/tests/ui/redundant_as_str.fixed
@@ -1,4 +1,5 @@
 #![warn(clippy::redundant_as_str)]
+#![allow(clippy::const_is_empty)]
 
 fn main() {
     let string = "Hello, world!".to_owned();
diff --git a/src/tools/clippy/tests/ui/redundant_as_str.rs b/src/tools/clippy/tests/ui/redundant_as_str.rs
index 7a74d8a55de..257af591cef 100644
--- a/src/tools/clippy/tests/ui/redundant_as_str.rs
+++ b/src/tools/clippy/tests/ui/redundant_as_str.rs
@@ -1,4 +1,5 @@
 #![warn(clippy::redundant_as_str)]
+#![allow(clippy::const_is_empty)]
 
 fn main() {
     let string = "Hello, world!".to_owned();
diff --git a/src/tools/clippy/tests/ui/redundant_as_str.stderr b/src/tools/clippy/tests/ui/redundant_as_str.stderr
index f086de5fede..f5379d701db 100644
--- a/src/tools/clippy/tests/ui/redundant_as_str.stderr
+++ b/src/tools/clippy/tests/ui/redundant_as_str.stderr
@@ -1,5 +1,5 @@
 error: this `as_str` is redundant and can be removed as the method immediately following exists on `String` too
-  --> tests/ui/redundant_as_str.rs:7:29
+  --> tests/ui/redundant_as_str.rs:8:29
    |
 LL |     let _redundant = string.as_str().as_bytes();
    |                             ^^^^^^^^^^^^^^^^^ help: try: `as_bytes`
@@ -8,7 +8,7 @@ LL |     let _redundant = string.as_str().as_bytes();
    = help: to override `-D warnings` add `#[allow(clippy::redundant_as_str)]`
 
 error: this `as_str` is redundant and can be removed as the method immediately following exists on `String` too
-  --> tests/ui/redundant_as_str.rs:8:29
+  --> tests/ui/redundant_as_str.rs:9:29
    |
 LL |     let _redundant = string.as_str().is_empty();
    |                             ^^^^^^^^^^^^^^^^^ help: try: `is_empty`
diff --git a/src/tools/clippy/tests/ui/rename.fixed b/src/tools/clippy/tests/ui/rename.fixed
index f4ff0f0b88b..24d0f797542 100644
--- a/src/tools/clippy/tests/ui/rename.fixed
+++ b/src/tools/clippy/tests/ui/rename.fixed
@@ -2,6 +2,7 @@
 // Use that command to update this file and do not edit by hand.
 // Manual edits will be overwritten.
 
+#![allow(clippy::duplicated_attributes)]
 #![allow(clippy::almost_complete_range)]
 #![allow(clippy::disallowed_names)]
 #![allow(clippy::blocks_in_conditions)]
diff --git a/src/tools/clippy/tests/ui/rename.rs b/src/tools/clippy/tests/ui/rename.rs
index 0df1098f5fb..be8da2fa1a3 100644
--- a/src/tools/clippy/tests/ui/rename.rs
+++ b/src/tools/clippy/tests/ui/rename.rs
@@ -2,6 +2,7 @@
 // Use that command to update this file and do not edit by hand.
 // Manual edits will be overwritten.
 
+#![allow(clippy::duplicated_attributes)]
 #![allow(clippy::almost_complete_range)]
 #![allow(clippy::disallowed_names)]
 #![allow(clippy::blocks_in_conditions)]
diff --git a/src/tools/clippy/tests/ui/rename.stderr b/src/tools/clippy/tests/ui/rename.stderr
index e6659b109e5..777ac20153d 100644
--- a/src/tools/clippy/tests/ui/rename.stderr
+++ b/src/tools/clippy/tests/ui/rename.stderr
@@ -1,5 +1,5 @@
 error: lint `clippy::almost_complete_letter_range` has been renamed to `clippy::almost_complete_range`
-  --> tests/ui/rename.rs:55:9
+  --> tests/ui/rename.rs:56:9
    |
 LL | #![warn(clippy::almost_complete_letter_range)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::almost_complete_range`
@@ -8,343 +8,343 @@ LL | #![warn(clippy::almost_complete_letter_range)]
    = help: to override `-D warnings` add `#[allow(renamed_and_removed_lints)]`
 
 error: lint `clippy::blacklisted_name` has been renamed to `clippy::disallowed_names`
-  --> tests/ui/rename.rs:56:9
+  --> tests/ui/rename.rs:57:9
    |
 LL | #![warn(clippy::blacklisted_name)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_names`
 
 error: lint `clippy::block_in_if_condition_expr` has been renamed to `clippy::blocks_in_conditions`
-  --> tests/ui/rename.rs:57:9
+  --> tests/ui/rename.rs:58:9
    |
 LL | #![warn(clippy::block_in_if_condition_expr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_conditions`
 
 error: lint `clippy::block_in_if_condition_stmt` has been renamed to `clippy::blocks_in_conditions`
-  --> tests/ui/rename.rs:58:9
+  --> tests/ui/rename.rs:59:9
    |
 LL | #![warn(clippy::block_in_if_condition_stmt)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_conditions`
 
 error: lint `clippy::blocks_in_if_conditions` has been renamed to `clippy::blocks_in_conditions`
-  --> tests/ui/rename.rs:59:9
+  --> tests/ui/rename.rs:60:9
    |
 LL | #![warn(clippy::blocks_in_if_conditions)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::blocks_in_conditions`
 
 error: lint `clippy::box_vec` has been renamed to `clippy::box_collection`
-  --> tests/ui/rename.rs:60:9
+  --> tests/ui/rename.rs:61:9
    |
 LL | #![warn(clippy::box_vec)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::box_collection`
 
 error: lint `clippy::const_static_lifetime` has been renamed to `clippy::redundant_static_lifetimes`
-  --> tests/ui/rename.rs:61:9
+  --> tests/ui/rename.rs:62:9
    |
 LL | #![warn(clippy::const_static_lifetime)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::redundant_static_lifetimes`
 
 error: lint `clippy::cyclomatic_complexity` has been renamed to `clippy::cognitive_complexity`
-  --> tests/ui/rename.rs:62:9
+  --> tests/ui/rename.rs:63:9
    |
 LL | #![warn(clippy::cyclomatic_complexity)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::cognitive_complexity`
 
 error: lint `clippy::derive_hash_xor_eq` has been renamed to `clippy::derived_hash_with_manual_eq`
-  --> tests/ui/rename.rs:63:9
+  --> tests/ui/rename.rs:64:9
    |
 LL | #![warn(clippy::derive_hash_xor_eq)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::derived_hash_with_manual_eq`
 
 error: lint `clippy::disallowed_method` has been renamed to `clippy::disallowed_methods`
-  --> tests/ui/rename.rs:64:9
+  --> tests/ui/rename.rs:65:9
    |
 LL | #![warn(clippy::disallowed_method)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_methods`
 
 error: lint `clippy::disallowed_type` has been renamed to `clippy::disallowed_types`
-  --> tests/ui/rename.rs:65:9
+  --> tests/ui/rename.rs:66:9
    |
 LL | #![warn(clippy::disallowed_type)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::disallowed_types`
 
 error: lint `clippy::eval_order_dependence` has been renamed to `clippy::mixed_read_write_in_expression`
-  --> tests/ui/rename.rs:66:9
+  --> tests/ui/rename.rs:67:9
    |
 LL | #![warn(clippy::eval_order_dependence)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::mixed_read_write_in_expression`
 
 error: lint `clippy::identity_conversion` has been renamed to `clippy::useless_conversion`
-  --> tests/ui/rename.rs:67:9
+  --> tests/ui/rename.rs:68:9
    |
 LL | #![warn(clippy::identity_conversion)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::useless_conversion`
 
 error: lint `clippy::if_let_some_result` has been renamed to `clippy::match_result_ok`
-  --> tests/ui/rename.rs:68:9
+  --> tests/ui/rename.rs:69:9
    |
 LL | #![warn(clippy::if_let_some_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::match_result_ok`
 
 error: lint `clippy::incorrect_clone_impl_on_copy_type` has been renamed to `clippy::non_canonical_clone_impl`
-  --> tests/ui/rename.rs:69:9
+  --> tests/ui/rename.rs:70:9
    |
 LL | #![warn(clippy::incorrect_clone_impl_on_copy_type)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::non_canonical_clone_impl`
 
 error: lint `clippy::incorrect_partial_ord_impl_on_ord_type` has been renamed to `clippy::non_canonical_partial_ord_impl`
-  --> tests/ui/rename.rs:70:9
+  --> tests/ui/rename.rs:71:9
    |
 LL | #![warn(clippy::incorrect_partial_ord_impl_on_ord_type)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::non_canonical_partial_ord_impl`
 
 error: lint `clippy::integer_arithmetic` has been renamed to `clippy::arithmetic_side_effects`
-  --> tests/ui/rename.rs:71:9
+  --> tests/ui/rename.rs:72:9
    |
 LL | #![warn(clippy::integer_arithmetic)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::arithmetic_side_effects`
 
 error: lint `clippy::logic_bug` has been renamed to `clippy::overly_complex_bool_expr`
-  --> tests/ui/rename.rs:72:9
+  --> tests/ui/rename.rs:73:9
    |
 LL | #![warn(clippy::logic_bug)]
    |         ^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::overly_complex_bool_expr`
 
 error: lint `clippy::new_without_default_derive` has been renamed to `clippy::new_without_default`
-  --> tests/ui/rename.rs:73:9
+  --> tests/ui/rename.rs:74:9
    |
 LL | #![warn(clippy::new_without_default_derive)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::new_without_default`
 
 error: lint `clippy::option_and_then_some` has been renamed to `clippy::bind_instead_of_map`
-  --> tests/ui/rename.rs:74:9
+  --> tests/ui/rename.rs:75:9
    |
 LL | #![warn(clippy::option_and_then_some)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::bind_instead_of_map`
 
 error: lint `clippy::option_expect_used` has been renamed to `clippy::expect_used`
-  --> tests/ui/rename.rs:75:9
+  --> tests/ui/rename.rs:76:9
    |
 LL | #![warn(clippy::option_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::option_map_unwrap_or` has been renamed to `clippy::map_unwrap_or`
-  --> tests/ui/rename.rs:76:9
+  --> tests/ui/rename.rs:77:9
    |
 LL | #![warn(clippy::option_map_unwrap_or)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> tests/ui/rename.rs:77:9
+  --> tests/ui/rename.rs:78:9
    |
 LL | #![warn(clippy::option_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::option_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> tests/ui/rename.rs:78:9
+  --> tests/ui/rename.rs:79:9
    |
 LL | #![warn(clippy::option_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::ref_in_deref` has been renamed to `clippy::needless_borrow`
-  --> tests/ui/rename.rs:79:9
+  --> tests/ui/rename.rs:80:9
    |
 LL | #![warn(clippy::ref_in_deref)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::needless_borrow`
 
 error: lint `clippy::result_expect_used` has been renamed to `clippy::expect_used`
-  --> tests/ui/rename.rs:80:9
+  --> tests/ui/rename.rs:81:9
    |
 LL | #![warn(clippy::result_expect_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::expect_used`
 
 error: lint `clippy::result_map_unwrap_or_else` has been renamed to `clippy::map_unwrap_or`
-  --> tests/ui/rename.rs:81:9
+  --> tests/ui/rename.rs:82:9
    |
 LL | #![warn(clippy::result_map_unwrap_or_else)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::map_unwrap_or`
 
 error: lint `clippy::result_unwrap_used` has been renamed to `clippy::unwrap_used`
-  --> tests/ui/rename.rs:82:9
+  --> tests/ui/rename.rs:83:9
    |
 LL | #![warn(clippy::result_unwrap_used)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_used`
 
 error: lint `clippy::single_char_push_str` has been renamed to `clippy::single_char_add_str`
-  --> tests/ui/rename.rs:83:9
+  --> tests/ui/rename.rs:84:9
    |
 LL | #![warn(clippy::single_char_push_str)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::single_char_add_str`
 
 error: lint `clippy::stutter` has been renamed to `clippy::module_name_repetitions`
-  --> tests/ui/rename.rs:84:9
+  --> tests/ui/rename.rs:85:9
    |
 LL | #![warn(clippy::stutter)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `clippy::module_name_repetitions`
 
 error: lint `clippy::to_string_in_display` has been renamed to `clippy::recursive_format_impl`
-  --> tests/ui/rename.rs:85:9
+  --> tests/ui/rename.rs:86:9
    |
 LL | #![warn(clippy::to_string_in_display)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::recursive_format_impl`
 
 error: lint `clippy::unwrap_or_else_default` has been renamed to `clippy::unwrap_or_default`
-  --> tests/ui/rename.rs:86:9
+  --> tests/ui/rename.rs:87:9
    |
 LL | #![warn(clippy::unwrap_or_else_default)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::unwrap_or_default`
 
 error: lint `clippy::zero_width_space` has been renamed to `clippy::invisible_characters`
-  --> tests/ui/rename.rs:87:9
+  --> tests/ui/rename.rs:88:9
    |
 LL | #![warn(clippy::zero_width_space)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `clippy::invisible_characters`
 
 error: lint `clippy::cast_ref_to_mut` has been renamed to `invalid_reference_casting`
-  --> tests/ui/rename.rs:88:9
+  --> tests/ui/rename.rs:89:9
    |
 LL | #![warn(clippy::cast_ref_to_mut)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_reference_casting`
 
 error: lint `clippy::clone_double_ref` has been renamed to `suspicious_double_ref_op`
-  --> tests/ui/rename.rs:89:9
+  --> tests/ui/rename.rs:90:9
    |
 LL | #![warn(clippy::clone_double_ref)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `suspicious_double_ref_op`
 
 error: lint `clippy::cmp_nan` has been renamed to `invalid_nan_comparisons`
-  --> tests/ui/rename.rs:90:9
+  --> tests/ui/rename.rs:91:9
    |
 LL | #![warn(clippy::cmp_nan)]
    |         ^^^^^^^^^^^^^^^ help: use the new name: `invalid_nan_comparisons`
 
 error: lint `clippy::drop_bounds` has been renamed to `drop_bounds`
-  --> tests/ui/rename.rs:91:9
+  --> tests/ui/rename.rs:92:9
    |
 LL | #![warn(clippy::drop_bounds)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `drop_bounds`
 
 error: lint `clippy::drop_copy` has been renamed to `dropping_copy_types`
-  --> tests/ui/rename.rs:92:9
+  --> tests/ui/rename.rs:93:9
    |
 LL | #![warn(clippy::drop_copy)]
    |         ^^^^^^^^^^^^^^^^^ help: use the new name: `dropping_copy_types`
 
 error: lint `clippy::drop_ref` has been renamed to `dropping_references`
-  --> tests/ui/rename.rs:93:9
+  --> tests/ui/rename.rs:94:9
    |
 LL | #![warn(clippy::drop_ref)]
    |         ^^^^^^^^^^^^^^^^ help: use the new name: `dropping_references`
 
 error: lint `clippy::fn_null_check` has been renamed to `useless_ptr_null_checks`
-  --> tests/ui/rename.rs:94:9
+  --> tests/ui/rename.rs:95:9
    |
 LL | #![warn(clippy::fn_null_check)]
    |         ^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `useless_ptr_null_checks`
 
 error: lint `clippy::for_loop_over_option` has been renamed to `for_loops_over_fallibles`
-  --> tests/ui/rename.rs:95:9
+  --> tests/ui/rename.rs:96:9
    |
 LL | #![warn(clippy::for_loop_over_option)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::for_loop_over_result` has been renamed to `for_loops_over_fallibles`
-  --> tests/ui/rename.rs:96:9
+  --> tests/ui/rename.rs:97:9
    |
 LL | #![warn(clippy::for_loop_over_result)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::for_loops_over_fallibles` has been renamed to `for_loops_over_fallibles`
-  --> tests/ui/rename.rs:97:9
+  --> tests/ui/rename.rs:98:9
    |
 LL | #![warn(clippy::for_loops_over_fallibles)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `for_loops_over_fallibles`
 
 error: lint `clippy::forget_copy` has been renamed to `forgetting_copy_types`
-  --> tests/ui/rename.rs:98:9
+  --> tests/ui/rename.rs:99:9
    |
 LL | #![warn(clippy::forget_copy)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `forgetting_copy_types`
 
 error: lint `clippy::forget_ref` has been renamed to `forgetting_references`
-  --> tests/ui/rename.rs:99:9
+  --> tests/ui/rename.rs:100:9
    |
 LL | #![warn(clippy::forget_ref)]
    |         ^^^^^^^^^^^^^^^^^^ help: use the new name: `forgetting_references`
 
 error: lint `clippy::into_iter_on_array` has been renamed to `array_into_iter`
-  --> tests/ui/rename.rs:100:9
+  --> tests/ui/rename.rs:101:9
    |
 LL | #![warn(clippy::into_iter_on_array)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `array_into_iter`
 
 error: lint `clippy::invalid_atomic_ordering` has been renamed to `invalid_atomic_ordering`
-  --> tests/ui/rename.rs:101:9
+  --> tests/ui/rename.rs:102:9
    |
 LL | #![warn(clippy::invalid_atomic_ordering)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_atomic_ordering`
 
 error: lint `clippy::invalid_ref` has been renamed to `invalid_value`
-  --> tests/ui/rename.rs:102:9
+  --> tests/ui/rename.rs:103:9
    |
 LL | #![warn(clippy::invalid_ref)]
    |         ^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_value`
 
 error: lint `clippy::invalid_utf8_in_unchecked` has been renamed to `invalid_from_utf8_unchecked`
-  --> tests/ui/rename.rs:103:9
+  --> tests/ui/rename.rs:104:9
    |
 LL | #![warn(clippy::invalid_utf8_in_unchecked)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `invalid_from_utf8_unchecked`
 
 error: lint `clippy::let_underscore_drop` has been renamed to `let_underscore_drop`
-  --> tests/ui/rename.rs:104:9
+  --> tests/ui/rename.rs:105:9
    |
 LL | #![warn(clippy::let_underscore_drop)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `let_underscore_drop`
 
 error: lint `clippy::mem_discriminant_non_enum` has been renamed to `enum_intrinsics_non_enums`
-  --> tests/ui/rename.rs:105:9
+  --> tests/ui/rename.rs:106:9
    |
 LL | #![warn(clippy::mem_discriminant_non_enum)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `enum_intrinsics_non_enums`
 
 error: lint `clippy::panic_params` has been renamed to `non_fmt_panics`
-  --> tests/ui/rename.rs:106:9
+  --> tests/ui/rename.rs:107:9
    |
 LL | #![warn(clippy::panic_params)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `non_fmt_panics`
 
 error: lint `clippy::positional_named_format_parameters` has been renamed to `named_arguments_used_positionally`
-  --> tests/ui/rename.rs:107:9
+  --> tests/ui/rename.rs:108:9
    |
 LL | #![warn(clippy::positional_named_format_parameters)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `named_arguments_used_positionally`
 
 error: lint `clippy::temporary_cstring_as_ptr` has been renamed to `temporary_cstring_as_ptr`
-  --> tests/ui/rename.rs:108:9
+  --> tests/ui/rename.rs:109:9
    |
 LL | #![warn(clippy::temporary_cstring_as_ptr)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `temporary_cstring_as_ptr`
 
 error: lint `clippy::undropped_manually_drops` has been renamed to `undropped_manually_drops`
-  --> tests/ui/rename.rs:109:9
+  --> tests/ui/rename.rs:110:9
    |
 LL | #![warn(clippy::undropped_manually_drops)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `undropped_manually_drops`
 
 error: lint `clippy::unknown_clippy_lints` has been renamed to `unknown_lints`
-  --> tests/ui/rename.rs:110:9
+  --> tests/ui/rename.rs:111:9
    |
 LL | #![warn(clippy::unknown_clippy_lints)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unknown_lints`
 
 error: lint `clippy::unused_label` has been renamed to `unused_labels`
-  --> tests/ui/rename.rs:111:9
+  --> tests/ui/rename.rs:112:9
    |
 LL | #![warn(clippy::unused_label)]
    |         ^^^^^^^^^^^^^^^^^^^^ help: use the new name: `unused_labels`
 
 error: lint `clippy::vtable_address_comparisons` has been renamed to `ambiguous_wide_pointer_comparisons`
-  --> tests/ui/rename.rs:112:9
+  --> tests/ui/rename.rs:113:9
    |
 LL | #![warn(clippy::vtable_address_comparisons)]
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the new name: `ambiguous_wide_pointer_comparisons`
diff --git a/src/tools/clippy/tests/ui/single_match.fixed b/src/tools/clippy/tests/ui/single_match.fixed
index 6df64eb4053..acd70416d8b 100644
--- a/src/tools/clippy/tests/ui/single_match.fixed
+++ b/src/tools/clippy/tests/ui/single_match.fixed
@@ -1,12 +1,11 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::single_match)]
 #![allow(
     unused,
     clippy::uninlined_format_args,
     clippy::needless_if,
     clippy::redundant_guards,
-    clippy::redundant_pattern_matching
+    clippy::redundant_pattern_matching,
+    clippy::manual_unwrap_or_default
 )]
 fn dummy() {}
 
diff --git a/src/tools/clippy/tests/ui/single_match.rs b/src/tools/clippy/tests/ui/single_match.rs
index 4f005f4e04f..bde78199810 100644
--- a/src/tools/clippy/tests/ui/single_match.rs
+++ b/src/tools/clippy/tests/ui/single_match.rs
@@ -1,12 +1,11 @@
-//@compile-flags: -Zdeduplicate-diagnostics=yes
-
 #![warn(clippy::single_match)]
 #![allow(
     unused,
     clippy::uninlined_format_args,
     clippy::needless_if,
     clippy::redundant_guards,
-    clippy::redundant_pattern_matching
+    clippy::redundant_pattern_matching,
+    clippy::manual_unwrap_or_default
 )]
 fn dummy() {}
 
diff --git a/src/tools/clippy/tests/ui/single_match.stderr b/src/tools/clippy/tests/ui/single_match.stderr
index 651d0b4911d..a249c120ee4 100644
--- a/src/tools/clippy/tests/ui/single_match.stderr
+++ b/src/tools/clippy/tests/ui/single_match.stderr
@@ -1,5 +1,5 @@
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:16:5
+  --> tests/ui/single_match.rs:15:5
    |
 LL | /     match x {
 LL | |         Some(y) => {
@@ -19,7 +19,7 @@ LL ~     };
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:24:5
+  --> tests/ui/single_match.rs:23:5
    |
 LL | /     match x {
 LL | |         // Note the missing block braces.
@@ -31,7 +31,7 @@ LL | |     }
    | |_____^ help: try: `if let Some(y) = x { println!("{:?}", y) }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:33:5
+  --> tests/ui/single_match.rs:32:5
    |
 LL | /     match z {
 LL | |         (2..=3, 7..=9) => dummy(),
@@ -40,7 +40,7 @@ LL | |     };
    | |_____^ help: try: `if let (2..=3, 7..=9) = z { dummy() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:62:5
+  --> tests/ui/single_match.rs:61:5
    |
 LL | /     match x {
 LL | |         Some(y) => dummy(),
@@ -49,7 +49,7 @@ LL | |     };
    | |_____^ help: try: `if let Some(y) = x { dummy() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:67:5
+  --> tests/ui/single_match.rs:66:5
    |
 LL | /     match y {
 LL | |         Ok(y) => dummy(),
@@ -58,7 +58,7 @@ LL | |     };
    | |_____^ help: try: `if let Ok(y) = y { dummy() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:74:5
+  --> tests/ui/single_match.rs:73:5
    |
 LL | /     match c {
 LL | |         Cow::Borrowed(..) => dummy(),
@@ -67,7 +67,7 @@ LL | |     };
    | |_____^ help: try: `if let Cow::Borrowed(..) = c { dummy() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:95:5
+  --> tests/ui/single_match.rs:94:5
    |
 LL | /     match x {
 LL | |         "test" => println!(),
@@ -76,7 +76,7 @@ LL | |     }
    | |_____^ help: try: `if x == "test" { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:108:5
+  --> tests/ui/single_match.rs:107:5
    |
 LL | /     match x {
 LL | |         Foo::A => println!(),
@@ -85,7 +85,7 @@ LL | |     }
    | |_____^ help: try: `if x == Foo::A { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:114:5
+  --> tests/ui/single_match.rs:113:5
    |
 LL | /     match x {
 LL | |         FOO_C => println!(),
@@ -94,7 +94,7 @@ LL | |     }
    | |_____^ help: try: `if x == FOO_C { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:119:5
+  --> tests/ui/single_match.rs:118:5
    |
 LL | /     match &&x {
 LL | |         Foo::A => println!(),
@@ -103,7 +103,7 @@ LL | |     }
    | |_____^ help: try: `if x == Foo::A { println!() }`
 
 error: you seem to be trying to use `match` for an equality check. Consider using `if`
-  --> tests/ui/single_match.rs:125:5
+  --> tests/ui/single_match.rs:124:5
    |
 LL | /     match &x {
 LL | |         Foo::A => println!(),
@@ -112,7 +112,7 @@ LL | |     }
    | |_____^ help: try: `if x == &Foo::A { println!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:142:5
+  --> tests/ui/single_match.rs:141:5
    |
 LL | /     match x {
 LL | |         Bar::A => println!(),
@@ -121,7 +121,7 @@ LL | |     }
    | |_____^ help: try: `if let Bar::A = x { println!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:150:5
+  --> tests/ui/single_match.rs:149:5
    |
 LL | /     match x {
 LL | |         None => println!(),
@@ -130,7 +130,7 @@ LL | |     };
    | |_____^ help: try: `if let None = x { println!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:172:5
+  --> tests/ui/single_match.rs:171:5
    |
 LL | /     match x {
 LL | |         (Some(_), _) => {},
@@ -139,7 +139,7 @@ LL | |     }
    | |_____^ help: try: `if let (Some(_), _) = x {}`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:178:5
+  --> tests/ui/single_match.rs:177:5
    |
 LL | /     match x {
 LL | |         (Some(E::V), _) => todo!(),
@@ -148,7 +148,7 @@ LL | |     }
    | |_____^ help: try: `if let (Some(E::V), _) = x { todo!() }`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:184:5
+  --> tests/ui/single_match.rs:183:5
    |
 LL | /     match (Some(42), Some(E::V), Some(42)) {
 LL | |         (.., Some(E::V), _) => {},
@@ -157,7 +157,7 @@ LL | |     }
    | |_____^ help: try: `if let (.., Some(E::V), _) = (Some(42), Some(E::V), Some(42)) {}`
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:256:5
+  --> tests/ui/single_match.rs:255:5
    |
 LL | /     match bar {
 LL | |         Some(v) => unsafe {
@@ -177,7 +177,7 @@ LL +     } }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match.rs:264:5
+  --> tests/ui/single_match.rs:263:5
    |
 LL | /     match bar {
 LL | |         #[rustfmt::skip]
diff --git a/src/tools/clippy/tests/ui/single_match_else.fixed b/src/tools/clippy/tests/ui/single_match_else.fixed
index 2970f5485fa..e840adf0fa3 100644
--- a/src/tools/clippy/tests/ui/single_match_else.fixed
+++ b/src/tools/clippy/tests/ui/single_match_else.fixed
@@ -1,5 +1,4 @@
 //@aux-build: proc_macros.rs
-//@compile-flags: -Zdeduplicate-diagnostics=yes
 
 #![warn(clippy::single_match_else)]
 #![allow(unused, clippy::needless_return, clippy::no_effect, clippy::uninlined_format_args)]
diff --git a/src/tools/clippy/tests/ui/single_match_else.rs b/src/tools/clippy/tests/ui/single_match_else.rs
index 26974b2a48a..430c4da20f1 100644
--- a/src/tools/clippy/tests/ui/single_match_else.rs
+++ b/src/tools/clippy/tests/ui/single_match_else.rs
@@ -1,5 +1,4 @@
 //@aux-build: proc_macros.rs
-//@compile-flags: -Zdeduplicate-diagnostics=yes
 
 #![warn(clippy::single_match_else)]
 #![allow(unused, clippy::needless_return, clippy::no_effect, clippy::uninlined_format_args)]
diff --git a/src/tools/clippy/tests/ui/single_match_else.stderr b/src/tools/clippy/tests/ui/single_match_else.stderr
index 48c74c0caea..f8f88379d6d 100644
--- a/src/tools/clippy/tests/ui/single_match_else.stderr
+++ b/src/tools/clippy/tests/ui/single_match_else.stderr
@@ -1,5 +1,5 @@
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:18:13
+  --> tests/ui/single_match_else.rs:17:13
    |
 LL |       let _ = match ExprNode::Butterflies {
    |  _____________^
@@ -22,7 +22,7 @@ LL ~     };
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:83:5
+  --> tests/ui/single_match_else.rs:82:5
    |
 LL | /     match Some(1) {
 LL | |         Some(a) => println!("${:?}", a),
@@ -42,7 +42,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:92:5
+  --> tests/ui/single_match_else.rs:91:5
    |
 LL | /     match Some(1) {
 LL | |         Some(a) => println!("${:?}", a),
@@ -62,7 +62,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:102:5
+  --> tests/ui/single_match_else.rs:101:5
    |
 LL | /     match Result::<i32, Infallible>::Ok(1) {
 LL | |         Ok(a) => println!("${:?}", a),
@@ -82,7 +82,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:111:5
+  --> tests/ui/single_match_else.rs:110:5
    |
 LL | /     match Cow::from("moo") {
 LL | |         Cow::Owned(a) => println!("${:?}", a),
@@ -102,7 +102,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:121:5
+  --> tests/ui/single_match_else.rs:120:5
    |
 LL | /     match bar {
 LL | |         Some(v) => unsafe {
@@ -125,7 +125,7 @@ LL +     }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:132:5
+  --> tests/ui/single_match_else.rs:131:5
    |
 LL | /     match bar {
 LL | |         Some(v) => {
@@ -149,7 +149,7 @@ LL +     } }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:144:5
+  --> tests/ui/single_match_else.rs:143:5
    |
 LL | /     match bar {
 LL | |         Some(v) => unsafe {
@@ -173,7 +173,7 @@ LL +     } }
    |
 
 error: you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`
-  --> tests/ui/single_match_else.rs:156:5
+  --> tests/ui/single_match_else.rs:155:5
    |
 LL | /     match bar {
 LL | |         #[rustfmt::skip]
diff --git a/src/tools/clippy/tests/ui/std_instead_of_core.fixed b/src/tools/clippy/tests/ui/std_instead_of_core.fixed
index 0a734a65d29..ec4ae2ea13c 100644
--- a/src/tools/clippy/tests/ui/std_instead_of_core.fixed
+++ b/src/tools/clippy/tests/ui/std_instead_of_core.fixed
@@ -17,7 +17,7 @@ fn std_instead_of_core() {
     use ::core::hash::Hash;
     //~^ ERROR: used import from `std` instead of `core`
     // Don't lint on `env` macro
-    use core::env;
+    use std::env;
 
     // Multiple imports
     use core::fmt::{Debug, Result};
diff --git a/src/tools/clippy/tests/ui/std_instead_of_core.stderr b/src/tools/clippy/tests/ui/std_instead_of_core.stderr
index ee42b474a32..8f920511cc5 100644
--- a/src/tools/clippy/tests/ui/std_instead_of_core.stderr
+++ b/src/tools/clippy/tests/ui/std_instead_of_core.stderr
@@ -14,12 +14,6 @@ LL |     use ::std::hash::Hash;
    |           ^^^ help: consider importing the item from `core`: `core`
 
 error: used import from `std` instead of `core`
-  --> tests/ui/std_instead_of_core.rs:20:9
-   |
-LL |     use std::env;
-   |         ^^^ help: consider importing the item from `core`: `core`
-
-error: used import from `std` instead of `core`
   --> tests/ui/std_instead_of_core.rs:23:9
    |
 LL |     use std::fmt::{Debug, Result};
@@ -85,5 +79,5 @@ LL |     use alloc::slice::from_ref;
    = note: `-D clippy::alloc-instead-of-core` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::alloc_instead_of_core)]`
 
-error: aborting due to 13 previous errors
+error: aborting due to 12 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unconditional_recursion.rs b/src/tools/clippy/tests/ui/unconditional_recursion.rs
index 35275e81ded..70b390b00e2 100644
--- a/src/tools/clippy/tests/ui/unconditional_recursion.rs
+++ b/src/tools/clippy/tests/ui/unconditional_recursion.rs
@@ -1,7 +1,11 @@
 //@no-rustfix
 
 #![warn(clippy::unconditional_recursion)]
-#![allow(clippy::partialeq_ne_impl, clippy::default_constructed_unit_structs)]
+#![allow(
+    clippy::partialeq_ne_impl,
+    clippy::default_constructed_unit_structs,
+    clippy::only_used_in_recursion
+)]
 
 enum Foo {
     A,
@@ -350,4 +354,48 @@ mod issue12154 {
     }
 }
 
+// From::from -> Into::into -> From::from
+struct BadFromTy1<'a>(&'a ());
+struct BadIntoTy1<'b>(&'b ());
+impl<'a> From<BadFromTy1<'a>> for BadIntoTy1<'static> {
+    fn from(f: BadFromTy1<'a>) -> Self {
+        f.into()
+    }
+}
+
+// Using UFCS syntax
+struct BadFromTy2<'a>(&'a ());
+struct BadIntoTy2<'b>(&'b ());
+impl<'a> From<BadFromTy2<'a>> for BadIntoTy2<'static> {
+    fn from(f: BadFromTy2<'a>) -> Self {
+        Into::into(f)
+    }
+}
+
+// Different Into impl (<i16 as Into<i32>>), so no infinite recursion
+struct BadFromTy3;
+impl From<BadFromTy3> for i32 {
+    fn from(f: BadFromTy3) -> Self {
+        Into::into(1i16)
+    }
+}
+
+// A conditional return that ends the recursion
+struct BadFromTy4;
+impl From<BadFromTy4> for i32 {
+    fn from(f: BadFromTy4) -> Self {
+        if true {
+            return 42;
+        }
+        f.into()
+    }
+}
+
+// Types differ in refs, don't lint
+impl From<&BadFromTy4> for i32 {
+    fn from(f: &BadFromTy4) -> Self {
+        BadFromTy4.into()
+    }
+}
+
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/unconditional_recursion.stderr b/src/tools/clippy/tests/ui/unconditional_recursion.stderr
index 3fd6c91000e..03c27bd8ed8 100644
--- a/src/tools/clippy/tests/ui/unconditional_recursion.stderr
+++ b/src/tools/clippy/tests/ui/unconditional_recursion.stderr
@@ -1,5 +1,5 @@
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:42:5
+  --> tests/ui/unconditional_recursion.rs:46:5
    |
 LL |     fn ne(&self, other: &Self) -> bool {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@@ -12,7 +12,7 @@ LL |         self.ne(other)
    = help: to override `-D warnings` add `#[allow(unconditional_recursion)]`
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:46:5
+  --> tests/ui/unconditional_recursion.rs:50:5
    |
 LL |     fn eq(&self, other: &Self) -> bool {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@@ -23,7 +23,7 @@ LL |         self.eq(other)
    = help: a `loop` may express intention better if this is on purpose
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:211:5
+  --> tests/ui/unconditional_recursion.rs:215:5
    |
 LL |     fn to_string(&self) -> String {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@@ -34,7 +34,7 @@ LL |         self.to_string()
    = help: a `loop` may express intention better if this is on purpose
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:221:5
+  --> tests/ui/unconditional_recursion.rs:225:5
    |
 LL |     fn to_string(&self) -> String {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@@ -45,7 +45,7 @@ LL |         x.to_string()
    = help: a `loop` may express intention better if this is on purpose
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:232:5
+  --> tests/ui/unconditional_recursion.rs:236:5
    |
 LL |     fn to_string(&self) -> String {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@@ -56,7 +56,7 @@ LL |         (self as &Self).to_string()
    = help: a `loop` may express intention better if this is on purpose
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:12:5
+  --> tests/ui/unconditional_recursion.rs:16:5
    |
 LL | /     fn ne(&self, other: &Self) -> bool {
 LL | |
@@ -65,7 +65,7 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:14:9
+  --> tests/ui/unconditional_recursion.rs:18:9
    |
 LL |         self != other
    |         ^^^^^^^^^^^^^
@@ -73,7 +73,7 @@ LL |         self != other
    = help: to override `-D warnings` add `#[allow(clippy::unconditional_recursion)]`
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:16:5
+  --> tests/ui/unconditional_recursion.rs:20:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -82,13 +82,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:18:9
+  --> tests/ui/unconditional_recursion.rs:22:9
    |
 LL |         self == other
    |         ^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:28:5
+  --> tests/ui/unconditional_recursion.rs:32:5
    |
 LL | /     fn ne(&self, other: &Self) -> bool {
 LL | |         self != &Foo2::B // no error here
@@ -96,13 +96,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:29:9
+  --> tests/ui/unconditional_recursion.rs:33:9
    |
 LL |         self != &Foo2::B // no error here
    |         ^^^^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:31:5
+  --> tests/ui/unconditional_recursion.rs:35:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |         self == &Foo2::B // no error here
@@ -110,13 +110,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:32:9
+  --> tests/ui/unconditional_recursion.rs:36:9
    |
 LL |         self == &Foo2::B // no error here
    |         ^^^^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:42:5
+  --> tests/ui/unconditional_recursion.rs:46:5
    |
 LL | /     fn ne(&self, other: &Self) -> bool {
 LL | |
@@ -125,27 +125,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:44:9
+  --> tests/ui/unconditional_recursion.rs:48:9
    |
 LL |         self.ne(other)
    |         ^^^^^^^^^^^^^^
 
-error: parameter is only used in recursion
-  --> tests/ui/unconditional_recursion.rs:42:18
-   |
-LL |     fn ne(&self, other: &Self) -> bool {
-   |                  ^^^^^ help: if this is intentional, prefix it with an underscore: `_other`
-   |
-note: parameter used here
-  --> tests/ui/unconditional_recursion.rs:44:17
-   |
-LL |         self.ne(other)
-   |                 ^^^^^
-   = note: `-D clippy::only-used-in-recursion` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(clippy::only_used_in_recursion)]`
-
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:46:5
+  --> tests/ui/unconditional_recursion.rs:50:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -154,25 +140,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:48:9
+  --> tests/ui/unconditional_recursion.rs:52:9
    |
 LL |         self.eq(other)
    |         ^^^^^^^^^^^^^^
 
-error: parameter is only used in recursion
-  --> tests/ui/unconditional_recursion.rs:46:18
-   |
-LL |     fn eq(&self, other: &Self) -> bool {
-   |                  ^^^^^ help: if this is intentional, prefix it with an underscore: `_other`
-   |
-note: parameter used here
-  --> tests/ui/unconditional_recursion.rs:48:17
-   |
-LL |         self.eq(other)
-   |                 ^^^^^
-
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:90:5
+  --> tests/ui/unconditional_recursion.rs:94:5
    |
 LL | /     fn ne(&self, other: &Self) -> bool {
 LL | |
@@ -181,13 +155,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:92:9
+  --> tests/ui/unconditional_recursion.rs:96:9
    |
 LL |         other != self
    |         ^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:94:5
+  --> tests/ui/unconditional_recursion.rs:98:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -196,13 +170,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:96:9
+  --> tests/ui/unconditional_recursion.rs:100:9
    |
 LL |         other == self
    |         ^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:104:5
+  --> tests/ui/unconditional_recursion.rs:108:5
    |
 LL | /     fn ne(&self, other: &Self) -> bool {
 LL | |
@@ -211,13 +185,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:106:9
+  --> tests/ui/unconditional_recursion.rs:110:9
    |
 LL |         other != other
    |         ^^^^^^^^^^^^^^
 
 error: equal expressions as operands to `!=`
-  --> tests/ui/unconditional_recursion.rs:106:9
+  --> tests/ui/unconditional_recursion.rs:110:9
    |
 LL |         other != other
    |         ^^^^^^^^^^^^^^
@@ -225,7 +199,7 @@ LL |         other != other
    = note: `#[deny(clippy::eq_op)]` on by default
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:108:5
+  --> tests/ui/unconditional_recursion.rs:112:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -234,19 +208,19 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:110:9
+  --> tests/ui/unconditional_recursion.rs:114:9
    |
 LL |         other == other
    |         ^^^^^^^^^^^^^^
 
 error: equal expressions as operands to `==`
-  --> tests/ui/unconditional_recursion.rs:110:9
+  --> tests/ui/unconditional_recursion.rs:114:9
    |
 LL |         other == other
    |         ^^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:117:5
+  --> tests/ui/unconditional_recursion.rs:121:5
    |
 LL | /     fn ne(&self, _other: &Self) -> bool {
 LL | |
@@ -255,19 +229,19 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:119:9
+  --> tests/ui/unconditional_recursion.rs:123:9
    |
 LL |         self != self
    |         ^^^^^^^^^^^^
 
 error: equal expressions as operands to `!=`
-  --> tests/ui/unconditional_recursion.rs:119:9
+  --> tests/ui/unconditional_recursion.rs:123:9
    |
 LL |         self != self
    |         ^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:121:5
+  --> tests/ui/unconditional_recursion.rs:125:5
    |
 LL | /     fn eq(&self, _other: &Self) -> bool {
 LL | |
@@ -276,19 +250,19 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:123:9
+  --> tests/ui/unconditional_recursion.rs:127:9
    |
 LL |         self == self
    |         ^^^^^^^^^^^^
 
 error: equal expressions as operands to `==`
-  --> tests/ui/unconditional_recursion.rs:123:9
+  --> tests/ui/unconditional_recursion.rs:127:9
    |
 LL |         self == self
    |         ^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:149:13
+  --> tests/ui/unconditional_recursion.rs:153:13
    |
 LL | /             fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -300,7 +274,7 @@ LL |   impl_partial_eq!(S5);
    |   -------------------- in this macro invocation
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:151:17
+  --> tests/ui/unconditional_recursion.rs:155:17
    |
 LL |                 self == other
    |                 ^^^^^^^^^^^^^
@@ -310,7 +284,7 @@ LL | impl_partial_eq!(S5);
    = note: this error originates in the macro `impl_partial_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:178:5
+  --> tests/ui/unconditional_recursion.rs:182:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -321,13 +295,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:182:9
+  --> tests/ui/unconditional_recursion.rs:186:9
    |
 LL |         mine == theirs
    |         ^^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:247:5
+  --> tests/ui/unconditional_recursion.rs:251:5
    |
 LL | /     fn new() -> Self {
 LL | |
@@ -336,13 +310,13 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:249:9
+  --> tests/ui/unconditional_recursion.rs:253:9
    |
 LL |         Self::default()
    |         ^^^^^^^^^^^^^^^
 
 error: function cannot return without recursing
-  --> tests/ui/unconditional_recursion.rs:286:5
+  --> tests/ui/unconditional_recursion.rs:290:5
    |
 LL | /     fn eq(&self, other: &Self) -> bool {
 LL | |
@@ -353,10 +327,38 @@ LL | |     }
    | |_____^
    |
 note: recursive call site
-  --> tests/ui/unconditional_recursion.rs:290:9
+  --> tests/ui/unconditional_recursion.rs:294:9
    |
 LL |         mine.eq(theirs)
    |         ^^^^^^^^^^^^^^^
 
+error: function cannot return without recursing
+  --> tests/ui/unconditional_recursion.rs:361:5
+   |
+LL | /     fn from(f: BadFromTy1<'a>) -> Self {
+LL | |         f.into()
+LL | |     }
+   | |_____^
+   |
+note: recursive call site
+  --> tests/ui/unconditional_recursion.rs:362:9
+   |
+LL |         f.into()
+   |         ^^^^^^^^
+
+error: function cannot return without recursing
+  --> tests/ui/unconditional_recursion.rs:370:5
+   |
+LL | /     fn from(f: BadFromTy2<'a>) -> Self {
+LL | |         Into::into(f)
+LL | |     }
+   | |_____^
+   |
+note: recursive call site
+  --> tests/ui/unconditional_recursion.rs:371:9
+   |
+LL |         Into::into(f)
+   |         ^^^^^^^^^^^^^
+
 error: aborting due to 27 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unused_enumerate_index.fixed b/src/tools/clippy/tests/ui/unused_enumerate_index.fixed
index d079807ab58..cffd02b0acc 100644
--- a/src/tools/clippy/tests/ui/unused_enumerate_index.fixed
+++ b/src/tools/clippy/tests/ui/unused_enumerate_index.fixed
@@ -1,8 +1,12 @@
-#![allow(unused)]
+#![allow(unused, clippy::map_identity)]
 #![warn(clippy::unused_enumerate_index)]
 
 use std::iter::Enumerate;
 
+fn get_enumerate() -> Enumerate<std::vec::IntoIter<i32>> {
+    vec![1].into_iter().enumerate()
+}
+
 fn main() {
     let v = [1, 2, 3];
     for x in v.iter() {
@@ -55,4 +59,48 @@ fn main() {
     for x in dummy {
         println!("{x}");
     }
+
+    let _ = vec![1, 2, 3].into_iter().map(|x| println!("{x}"));
+
+    let p = vec![1, 2, 3].into_iter();
+    p.map(|x| println!("{x}"));
+
+    // This shouldn't trigger the lint. `get_enumerate` may come from an external library on which we
+    // have no control.
+    let p = get_enumerate();
+    p.map(|(_, x)| println!("{x}"));
+
+    // This shouldn't trigger the lint. The `enumerate` call is in a different context.
+    macro_rules! mac {
+        () => {
+            [1].iter().enumerate()
+        };
+    }
+    _ = mac!().map(|(_, v)| v);
+
+    macro_rules! mac2 {
+        () => {
+            [1].iter()
+        };
+    }
+    _ = mac2!().map(|_v| {});
+
+    // This shouldn't trigger the lint because of the `allow`.
+    #[allow(clippy::unused_enumerate_index)]
+    let v = [1].iter().enumerate();
+    v.map(|(_, _x)| {});
+
+    // This should keep the explicit type of `x`.
+    let v = [1, 2, 3].iter().copied();
+    let x = v.map(|x: i32| x).sum::<i32>();
+    assert_eq!(x, 6);
+
+    // This should keep the explicit type of `x`.
+    let v = [1, 2, 3].iter().copied();
+    let x = v.map(|x: i32| x).sum::<i32>();
+    assert_eq!(x, 6);
+
+    let v = [1, 2, 3].iter().copied();
+    let x = v.map(|x| x).sum::<i32>();
+    assert_eq!(x, 6);
 }
diff --git a/src/tools/clippy/tests/ui/unused_enumerate_index.rs b/src/tools/clippy/tests/ui/unused_enumerate_index.rs
index 2d524da7632..f2b5f8b9124 100644
--- a/src/tools/clippy/tests/ui/unused_enumerate_index.rs
+++ b/src/tools/clippy/tests/ui/unused_enumerate_index.rs
@@ -1,8 +1,12 @@
-#![allow(unused)]
+#![allow(unused, clippy::map_identity)]
 #![warn(clippy::unused_enumerate_index)]
 
 use std::iter::Enumerate;
 
+fn get_enumerate() -> Enumerate<std::vec::IntoIter<i32>> {
+    vec![1].into_iter().enumerate()
+}
+
 fn main() {
     let v = [1, 2, 3];
     for (_, x) in v.iter().enumerate() {
@@ -55,4 +59,48 @@ fn main() {
     for (_, x) in dummy.enumerate() {
         println!("{x}");
     }
+
+    let _ = vec![1, 2, 3].into_iter().enumerate().map(|(_, x)| println!("{x}"));
+
+    let p = vec![1, 2, 3].into_iter().enumerate();
+    p.map(|(_, x)| println!("{x}"));
+
+    // This shouldn't trigger the lint. `get_enumerate` may come from an external library on which we
+    // have no control.
+    let p = get_enumerate();
+    p.map(|(_, x)| println!("{x}"));
+
+    // This shouldn't trigger the lint. The `enumerate` call is in a different context.
+    macro_rules! mac {
+        () => {
+            [1].iter().enumerate()
+        };
+    }
+    _ = mac!().map(|(_, v)| v);
+
+    macro_rules! mac2 {
+        () => {
+            [1].iter()
+        };
+    }
+    _ = mac2!().enumerate().map(|(_, _v)| {});
+
+    // This shouldn't trigger the lint because of the `allow`.
+    #[allow(clippy::unused_enumerate_index)]
+    let v = [1].iter().enumerate();
+    v.map(|(_, _x)| {});
+
+    // This should keep the explicit type of `x`.
+    let v = [1, 2, 3].iter().copied().enumerate();
+    let x = v.map(|(_, x): (usize, i32)| x).sum::<i32>();
+    assert_eq!(x, 6);
+
+    // This should keep the explicit type of `x`.
+    let v = [1, 2, 3].iter().copied().enumerate();
+    let x = v.map(|(_, x): (_, i32)| x).sum::<i32>();
+    assert_eq!(x, 6);
+
+    let v = [1, 2, 3].iter().copied().enumerate();
+    let x = v.map(|(_, x)| x).sum::<i32>();
+    assert_eq!(x, 6);
 }
diff --git a/src/tools/clippy/tests/ui/unused_enumerate_index.stderr b/src/tools/clippy/tests/ui/unused_enumerate_index.stderr
index 7bd7d29117e..6ec07dcbff0 100644
--- a/src/tools/clippy/tests/ui/unused_enumerate_index.stderr
+++ b/src/tools/clippy/tests/ui/unused_enumerate_index.stderr
@@ -1,5 +1,5 @@
 error: you seem to use `.enumerate()` and immediately discard the index
-  --> tests/ui/unused_enumerate_index.rs:8:19
+  --> tests/ui/unused_enumerate_index.rs:12:19
    |
 LL |     for (_, x) in v.iter().enumerate() {
    |                   ^^^^^^^^^^^^^^^^^^^^
@@ -12,7 +12,7 @@ LL |     for x in v.iter() {
    |         ~    ~~~~~~~~
 
 error: you seem to use `.enumerate()` and immediately discard the index
-  --> tests/ui/unused_enumerate_index.rs:55:19
+  --> tests/ui/unused_enumerate_index.rs:59:19
    |
 LL |     for (_, x) in dummy.enumerate() {
    |                   ^^^^^^^^^^^^^^^^^
@@ -22,5 +22,77 @@ help: remove the `.enumerate()` call
 LL |     for x in dummy {
    |         ~    ~~~~~
 
-error: aborting due to 2 previous errors
+error: you seem to use `.enumerate()` and immediately discard the index
+  --> tests/ui/unused_enumerate_index.rs:63:39
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().enumerate().map(|(_, x)| println!("{x}"));
+   |                                       ^^^^^^^^^^^
+   |
+help: remove the `.enumerate()` call
+   |
+LL -     let _ = vec![1, 2, 3].into_iter().enumerate().map(|(_, x)| println!("{x}"));
+LL +     let _ = vec![1, 2, 3].into_iter().map(|x| println!("{x}"));
+   |
+
+error: you seem to use `.enumerate()` and immediately discard the index
+  --> tests/ui/unused_enumerate_index.rs:65:39
+   |
+LL |     let p = vec![1, 2, 3].into_iter().enumerate();
+   |                                       ^^^^^^^^^^^
+   |
+help: remove the `.enumerate()` call
+   |
+LL ~     let p = vec![1, 2, 3].into_iter();
+LL ~     p.map(|x| println!("{x}"));
+   |
+
+error: you seem to use `.enumerate()` and immediately discard the index
+  --> tests/ui/unused_enumerate_index.rs:86:17
+   |
+LL |     _ = mac2!().enumerate().map(|(_, _v)| {});
+   |                 ^^^^^^^^^^^
+   |
+help: remove the `.enumerate()` call
+   |
+LL -     _ = mac2!().enumerate().map(|(_, _v)| {});
+LL +     _ = mac2!().map(|_v| {});
+   |
+
+error: you seem to use `.enumerate()` and immediately discard the index
+  --> tests/ui/unused_enumerate_index.rs:94:39
+   |
+LL |     let v = [1, 2, 3].iter().copied().enumerate();
+   |                                       ^^^^^^^^^^^
+   |
+help: remove the `.enumerate()` call
+   |
+LL ~     let v = [1, 2, 3].iter().copied();
+LL ~     let x = v.map(|x: i32| x).sum::<i32>();
+   |
+
+error: you seem to use `.enumerate()` and immediately discard the index
+  --> tests/ui/unused_enumerate_index.rs:99:39
+   |
+LL |     let v = [1, 2, 3].iter().copied().enumerate();
+   |                                       ^^^^^^^^^^^
+   |
+help: remove the `.enumerate()` call
+   |
+LL ~     let v = [1, 2, 3].iter().copied();
+LL ~     let x = v.map(|x: i32| x).sum::<i32>();
+   |
+
+error: you seem to use `.enumerate()` and immediately discard the index
+  --> tests/ui/unused_enumerate_index.rs:103:39
+   |
+LL |     let v = [1, 2, 3].iter().copied().enumerate();
+   |                                       ^^^^^^^^^^^
+   |
+help: remove the `.enumerate()` call
+   |
+LL ~     let v = [1, 2, 3].iter().copied();
+LL ~     let x = v.map(|x| x).sum::<i32>();
+   |
+
+error: aborting due to 8 previous errors
 
diff --git a/src/tools/clippy/tests/ui/unused_io_amount.rs b/src/tools/clippy/tests/ui/unused_io_amount.rs
index 7e5a10c911b..f5b200d5ffe 100644
--- a/src/tools/clippy/tests/ui/unused_io_amount.rs
+++ b/src/tools/clippy/tests/ui/unused_io_amount.rs
@@ -271,5 +271,10 @@ pub fn wildcards(rdr: &mut dyn std::io::Read) {
         }
     }
 }
+fn allow_works<F: std::io::Read>(mut f: F) {
+    let mut data = Vec::with_capacity(100);
+    #[allow(clippy::unused_io_amount)]
+    f.read(&mut data).unwrap();
+}
 
 fn main() {}
diff --git a/src/tools/clippy/tests/ui/unused_peekable.rs b/src/tools/clippy/tests/ui/unused_peekable.rs
index 131b51e01b6..5865bba4350 100644
--- a/src/tools/clippy/tests/ui/unused_peekable.rs
+++ b/src/tools/clippy/tests/ui/unused_peekable.rs
@@ -174,3 +174,9 @@ fn valid() {
     let mut peekable = std::iter::empty::<u32>().peekable();
     takes_dyn(&mut peekable);
 }
+
+fn allow_works() {
+    #[allow(clippy::unused_peekable)]
+    let iter = [1, 2, 3].iter().peekable();
+    iter;
+}
diff --git a/src/tools/clippy/tests/ui/use_self.fixed b/src/tools/clippy/tests/ui/use_self.fixed
index 787dd3ec7e6..6ea7857a238 100644
--- a/src/tools/clippy/tests/ui/use_self.fixed
+++ b/src/tools/clippy/tests/ui/use_self.fixed
@@ -6,7 +6,8 @@
     clippy::should_implement_trait,
     clippy::upper_case_acronyms,
     clippy::from_over_into,
-    clippy::self_named_constructors
+    clippy::self_named_constructors,
+    clippy::needless_lifetimes
 )]
 
 #[macro_use]
@@ -53,6 +54,7 @@ mod better {
 }
 
 mod lifetimes {
+    #[derive(Clone, Copy)]
     struct Foo<'a> {
         foo_str: &'a str,
     }
@@ -68,11 +70,19 @@ mod lifetimes {
             Foo { foo_str: "foo" }
         }
 
-        // FIXME: the lint does not handle lifetimed struct
-        // `Self` should be applicable here
-        fn clone(&self) -> Foo<'a> {
+        fn clone(&self) -> Self {
             Foo { foo_str: self.foo_str }
         }
+
+        // Cannot replace with `Self` because the lifetime is not `'a`.
+        fn eq<'b>(&self, other: Foo<'b>) -> bool {
+            let x: Foo<'_> = other;
+            self.foo_str == other.foo_str
+        }
+
+        fn f(&self) -> Foo<'_> {
+            *self
+        }
     }
 }
 
diff --git a/src/tools/clippy/tests/ui/use_self.rs b/src/tools/clippy/tests/ui/use_self.rs
index 39e182faea6..338cc00e45a 100644
--- a/src/tools/clippy/tests/ui/use_self.rs
+++ b/src/tools/clippy/tests/ui/use_self.rs
@@ -6,7 +6,8 @@
     clippy::should_implement_trait,
     clippy::upper_case_acronyms,
     clippy::from_over_into,
-    clippy::self_named_constructors
+    clippy::self_named_constructors,
+    clippy::needless_lifetimes
 )]
 
 #[macro_use]
@@ -53,6 +54,7 @@ mod better {
 }
 
 mod lifetimes {
+    #[derive(Clone, Copy)]
     struct Foo<'a> {
         foo_str: &'a str,
     }
@@ -68,11 +70,19 @@ mod lifetimes {
             Foo { foo_str: "foo" }
         }
 
-        // FIXME: the lint does not handle lifetimed struct
-        // `Self` should be applicable here
         fn clone(&self) -> Foo<'a> {
             Foo { foo_str: self.foo_str }
         }
+
+        // Cannot replace with `Self` because the lifetime is not `'a`.
+        fn eq<'b>(&self, other: Foo<'b>) -> bool {
+            let x: Foo<'_> = other;
+            self.foo_str == other.foo_str
+        }
+
+        fn f(&self) -> Foo<'_> {
+            *self
+        }
     }
 }
 
diff --git a/src/tools/clippy/tests/ui/use_self.stderr b/src/tools/clippy/tests/ui/use_self.stderr
index 8d045f05ed2..d7aa8410a47 100644
--- a/src/tools/clippy/tests/ui/use_self.stderr
+++ b/src/tools/clippy/tests/ui/use_self.stderr
@@ -1,5 +1,5 @@
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:21:21
+  --> tests/ui/use_self.rs:22:21
    |
 LL |         fn new() -> Foo {
    |                     ^^^ help: use the applicable keyword: `Self`
@@ -8,250 +8,256 @@ LL |         fn new() -> Foo {
    = help: to override `-D warnings` add `#[allow(clippy::use_self)]`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:22:13
+  --> tests/ui/use_self.rs:23:13
    |
 LL |             Foo {}
    |             ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:24:22
+  --> tests/ui/use_self.rs:25:22
    |
 LL |         fn test() -> Foo {
    |                      ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:25:13
+  --> tests/ui/use_self.rs:26:13
    |
 LL |             Foo::new()
    |             ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:30:25
+  --> tests/ui/use_self.rs:31:25
    |
 LL |         fn default() -> Foo {
    |                         ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:31:13
+  --> tests/ui/use_self.rs:32:13
    |
 LL |             Foo::new()
    |             ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:96:24
+  --> tests/ui/use_self.rs:73:28
+   |
+LL |         fn clone(&self) -> Foo<'a> {
+   |                            ^^^^^^^ help: use the applicable keyword: `Self`
+
+error: unnecessary structure name repetition
+  --> tests/ui/use_self.rs:106:24
    |
 LL |         fn bad(foos: &[Foo]) -> impl Iterator<Item = &Foo> {
    |                        ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:96:55
+  --> tests/ui/use_self.rs:106:55
    |
 LL |         fn bad(foos: &[Foo]) -> impl Iterator<Item = &Foo> {
    |                                                       ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:111:13
+  --> tests/ui/use_self.rs:121:13
    |
 LL |             TS(0)
    |             ^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:146:29
+  --> tests/ui/use_self.rs:156:29
    |
 LL |                 fn bar() -> Bar {
    |                             ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:147:21
+  --> tests/ui/use_self.rs:157:21
    |
 LL |                     Bar { foo: Foo {} }
    |                     ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:158:21
+  --> tests/ui/use_self.rs:168:21
    |
 LL |         fn baz() -> Foo {
    |                     ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:159:13
+  --> tests/ui/use_self.rs:169:13
    |
 LL |             Foo {}
    |             ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:176:21
+  --> tests/ui/use_self.rs:186:21
    |
 LL |             let _ = Enum::B(42);
    |                     ^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:177:21
+  --> tests/ui/use_self.rs:187:21
    |
 LL |             let _ = Enum::C { field: true };
    |                     ^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:178:21
+  --> tests/ui/use_self.rs:188:21
    |
 LL |             let _ = Enum::A;
    |                     ^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:220:13
+  --> tests/ui/use_self.rs:230:13
    |
 LL |             nested::A::fun_1();
    |             ^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:221:13
+  --> tests/ui/use_self.rs:231:13
    |
 LL |             nested::A::A;
    |             ^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:223:13
+  --> tests/ui/use_self.rs:233:13
    |
 LL |             nested::A {};
    |             ^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:242:13
+  --> tests/ui/use_self.rs:252:13
    |
 LL |             TestStruct::from_something()
    |             ^^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:256:25
+  --> tests/ui/use_self.rs:266:25
    |
 LL |         async fn g() -> S {
    |                         ^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:257:13
+  --> tests/ui/use_self.rs:267:13
    |
 LL |             S {}
    |             ^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:261:16
+  --> tests/ui/use_self.rs:271:16
    |
 LL |             &p[S::A..S::B]
    |                ^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:261:22
+  --> tests/ui/use_self.rs:271:22
    |
 LL |             &p[S::A..S::B]
    |                      ^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:284:29
+  --> tests/ui/use_self.rs:294:29
    |
 LL |         fn foo(value: T) -> Foo<T> {
    |                             ^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:285:13
+  --> tests/ui/use_self.rs:295:13
    |
 LL |             Foo::<T> { value }
    |             ^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:457:13
+  --> tests/ui/use_self.rs:467:13
    |
 LL |             A::new::<submod::B>(submod::B {})
    |             ^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:494:13
+  --> tests/ui/use_self.rs:504:13
    |
 LL |             S2::new()
    |             ^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:531:17
+  --> tests/ui/use_self.rs:541:17
    |
 LL |                 Foo::Bar => unimplemented!(),
    |                 ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:532:17
+  --> tests/ui/use_self.rs:542:17
    |
 LL |                 Foo::Baz => unimplemented!(),
    |                 ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:538:20
+  --> tests/ui/use_self.rs:548:20
    |
 LL |             if let Foo::Bar = self {
    |                    ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:562:17
+  --> tests/ui/use_self.rs:572:17
    |
 LL |                 Something::Num(n) => *n,
    |                 ^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:563:17
+  --> tests/ui/use_self.rs:573:17
    |
 LL |                 Something::TupleNums(n, _m) => *n,
    |                 ^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:564:17
+  --> tests/ui/use_self.rs:574:17
    |
 LL |                 Something::StructNums { one, two: _ } => *one,
    |                 ^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:570:17
+  --> tests/ui/use_self.rs:580:17
    |
 LL |                 crate::issue8845::Something::Num(n) => *n,
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:571:17
+  --> tests/ui/use_self.rs:581:17
    |
 LL |                 crate::issue8845::Something::TupleNums(n, _m) => *n,
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:572:17
+  --> tests/ui/use_self.rs:582:17
    |
 LL |                 crate::issue8845::Something::StructNums { one, two: _ } => *one,
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:588:17
+  --> tests/ui/use_self.rs:598:17
    |
 LL |             let Foo(x) = self;
    |                 ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:593:17
+  --> tests/ui/use_self.rs:603:17
    |
 LL |             let crate::issue8845::Foo(x) = self;
    |                 ^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:600:17
+  --> tests/ui/use_self.rs:610:17
    |
 LL |             let Bar { x, .. } = self;
    |                 ^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:605:17
+  --> tests/ui/use_self.rs:615:17
    |
 LL |             let crate::issue8845::Bar { x, .. } = self;
    |                 ^^^^^^^^^^^^^^^^^^^^^ help: use the applicable keyword: `Self`
 
 error: unnecessary structure name repetition
-  --> tests/ui/use_self.rs:644:17
+  --> tests/ui/use_self.rs:654:17
    |
 LL |                 E::A => {},
    |                 ^ help: use the applicable keyword: `Self`
 
-error: aborting due to 42 previous errors
+error: aborting due to 43 previous errors
 
diff --git a/src/tools/clippy/tests/ui/zero_repeat_side_effects.fixed b/src/tools/clippy/tests/ui/zero_repeat_side_effects.fixed
new file mode 100644
index 00000000000..6f132521926
--- /dev/null
+++ b/src/tools/clippy/tests/ui/zero_repeat_side_effects.fixed
@@ -0,0 +1,60 @@
+#![warn(clippy::zero_repeat_side_effects)]
+#![allow(clippy::unnecessary_operation)]
+#![allow(clippy::useless_vec)]
+#![allow(clippy::needless_late_init)]
+
+fn f() -> i32 {
+    println!("side effect");
+    10
+}
+
+fn main() {
+    const N: usize = 0;
+    const M: usize = 1;
+
+    // should trigger
+
+    // on arrays
+    f(); let a: [i32; 0] = [];
+    f(); let a: [i32; 0] = [];
+    let mut b;
+    f(); b = [] as [i32; 0];
+    f(); b = [] as [i32; 0];
+
+    // on vecs
+    // vecs dont support infering value of consts
+    f(); let c: std::vec::Vec<i32> = vec![];
+    let d;
+    f(); d = vec![] as std::vec::Vec<i32>;
+
+    // for macros
+    println!("side effect"); let e: [(); 0] = [];
+
+    // for nested calls
+    { f() }; let g: [i32; 0] = [];
+
+    // as function param
+    drop({ f(); vec![] as std::vec::Vec<i32> });
+
+    // when singled out/not part of assignment/local
+    { f(); vec![] as std::vec::Vec<i32> };
+    { f(); [] as [i32; 0] };
+    { f(); [] as [i32; 0] };
+
+    // should not trigger
+
+    // on arrays with > 0 repeat
+    let a = [f(); 1];
+    let a = [f(); M];
+    let mut b;
+    b = [f(); 1];
+    b = [f(); M];
+
+    // on vecs with > 0 repeat
+    let c = vec![f(); 1];
+    let d;
+    d = vec![f(); 1];
+
+    // as function param
+    drop(vec![f(); 1]);
+}
diff --git a/src/tools/clippy/tests/ui/zero_repeat_side_effects.rs b/src/tools/clippy/tests/ui/zero_repeat_side_effects.rs
new file mode 100644
index 00000000000..9d9c367375a
--- /dev/null
+++ b/src/tools/clippy/tests/ui/zero_repeat_side_effects.rs
@@ -0,0 +1,60 @@
+#![warn(clippy::zero_repeat_side_effects)]
+#![allow(clippy::unnecessary_operation)]
+#![allow(clippy::useless_vec)]
+#![allow(clippy::needless_late_init)]
+
+fn f() -> i32 {
+    println!("side effect");
+    10
+}
+
+fn main() {
+    const N: usize = 0;
+    const M: usize = 1;
+
+    // should trigger
+
+    // on arrays
+    let a = [f(); 0];
+    let a = [f(); N];
+    let mut b;
+    b = [f(); 0];
+    b = [f(); N];
+
+    // on vecs
+    // vecs dont support infering value of consts
+    let c = vec![f(); 0];
+    let d;
+    d = vec![f(); 0];
+
+    // for macros
+    let e = [println!("side effect"); 0];
+
+    // for nested calls
+    let g = [{ f() }; 0];
+
+    // as function param
+    drop(vec![f(); 0]);
+
+    // when singled out/not part of assignment/local
+    vec![f(); 0];
+    [f(); 0];
+    [f(); N];
+
+    // should not trigger
+
+    // on arrays with > 0 repeat
+    let a = [f(); 1];
+    let a = [f(); M];
+    let mut b;
+    b = [f(); 1];
+    b = [f(); M];
+
+    // on vecs with > 0 repeat
+    let c = vec![f(); 1];
+    let d;
+    d = vec![f(); 1];
+
+    // as function param
+    drop(vec![f(); 1]);
+}
diff --git a/src/tools/clippy/tests/ui/zero_repeat_side_effects.stderr b/src/tools/clippy/tests/ui/zero_repeat_side_effects.stderr
new file mode 100644
index 00000000000..afdc6054253
--- /dev/null
+++ b/src/tools/clippy/tests/ui/zero_repeat_side_effects.stderr
@@ -0,0 +1,77 @@
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:18:5
+   |
+LL |     let a = [f(); 0];
+   |     ^^^^^^^^^^^^^^^^^ help: consider using: `f(); let a: [i32; 0] = [];`
+   |
+   = note: `-D clippy::zero-repeat-side-effects` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::zero_repeat_side_effects)]`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:19:5
+   |
+LL |     let a = [f(); N];
+   |     ^^^^^^^^^^^^^^^^^ help: consider using: `f(); let a: [i32; 0] = [];`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:21:5
+   |
+LL |     b = [f(); 0];
+   |     ^^^^^^^^^^^^ help: consider using: `f(); b = [] as [i32; 0]`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:22:5
+   |
+LL |     b = [f(); N];
+   |     ^^^^^^^^^^^^ help: consider using: `f(); b = [] as [i32; 0]`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:26:5
+   |
+LL |     let c = vec![f(); 0];
+   |     ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `f(); let c: std::vec::Vec<i32> = vec![];`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:28:5
+   |
+LL |     d = vec![f(); 0];
+   |     ^^^^^^^^^^^^^^^^ help: consider using: `f(); d = vec![] as std::vec::Vec<i32>`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:31:5
+   |
+LL |     let e = [println!("side effect"); 0];
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `println!("side effect"); let e: [(); 0] = [];`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:34:5
+   |
+LL |     let g = [{ f() }; 0];
+   |     ^^^^^^^^^^^^^^^^^^^^^ help: consider using: `{ f() }; let g: [i32; 0] = [];`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:37:10
+   |
+LL |     drop(vec![f(); 0]);
+   |          ^^^^^^^^^^^^ help: consider using: `{ f(); vec![] as std::vec::Vec<i32> }`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:40:5
+   |
+LL |     vec![f(); 0];
+   |     ^^^^^^^^^^^^ help: consider using: `{ f(); vec![] as std::vec::Vec<i32> }`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:41:5
+   |
+LL |     [f(); 0];
+   |     ^^^^^^^^ help: consider using: `{ f(); [] as [i32; 0] }`
+
+error: function or method calls as the initial value in zero-sized array initializers may cause side effects
+  --> tests/ui/zero_repeat_side_effects.rs:42:5
+   |
+LL |     [f(); N];
+   |     ^^^^^^^^ help: consider using: `{ f(); [] as [i32; 0] }`
+
+error: aborting due to 12 previous errors
+
diff --git a/src/tools/clippy/triagebot.toml b/src/tools/clippy/triagebot.toml
index 1a81394af10..d455d967e30 100644
--- a/src/tools/clippy/triagebot.toml
+++ b/src/tools/clippy/triagebot.toml
@@ -19,7 +19,7 @@ new_pr = true
 
 [assign]
 contributing_url = "https://github.com/rust-lang/rust-clippy/blob/master/CONTRIBUTING.md"
-users_on_vacation = ["xFrednet"]
+users_on_vacation = []
 
 [assign.owners]
 "/.github" = ["@flip1995"]
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 0c590b0fda6..bd2f65925bb 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -198,6 +198,11 @@ pub fn compute_stamp_hash(config: &Config) -> String {
     format!("{:x}", hash.finish())
 }
 
+fn remove_and_create_dir_all(path: &Path) {
+    let _ = fs::remove_dir_all(path);
+    fs::create_dir_all(path).unwrap();
+}
+
 #[derive(Copy, Clone)]
 struct TestCx<'test> {
     config: &'test Config,
@@ -998,8 +1003,7 @@ impl<'test> TestCx<'test> {
         let mut rustc = Command::new(&self.config.rustc_path);
 
         let out_dir = self.output_base_name().with_extension("pretty-out");
-        let _ = fs::remove_dir_all(&out_dir);
-        create_dir_all(&out_dir).unwrap();
+        remove_and_create_dir_all(&out_dir);
 
         let target = if self.props.force_host { &*self.config.host } else { &*self.config.target };
 
@@ -2094,14 +2098,12 @@ impl<'test> TestCx<'test> {
         let aux_dir = self.aux_output_dir_name();
 
         if !self.props.aux_builds.is_empty() {
-            let _ = fs::remove_dir_all(&aux_dir);
-            create_dir_all(&aux_dir).unwrap();
+            remove_and_create_dir_all(&aux_dir);
         }
 
         if !self.props.aux_bins.is_empty() {
             let aux_bin_dir = self.aux_bin_output_dir_name();
-            let _ = fs::remove_dir_all(&aux_bin_dir);
-            create_dir_all(&aux_bin_dir).unwrap();
+            remove_and_create_dir_all(&aux_bin_dir);
         }
 
         aux_dir
@@ -2469,8 +2471,7 @@ impl<'test> TestCx<'test> {
                 }
 
                 let mir_dump_dir = self.get_mir_dump_dir();
-                let _ = fs::remove_dir_all(&mir_dump_dir);
-                create_dir_all(mir_dump_dir.as_path()).unwrap();
+                remove_and_create_dir_all(&mir_dump_dir);
                 let mut dir_opt = "-Zdump-mir-dir=".to_string();
                 dir_opt.push_str(mir_dump_dir.to_str().unwrap());
                 debug!("dir_opt: {:?}", dir_opt);
@@ -2951,8 +2952,7 @@ impl<'test> TestCx<'test> {
         assert!(self.revision.is_none(), "revisions not relevant here");
 
         let out_dir = self.output_base_dir();
-        let _ = fs::remove_dir_all(&out_dir);
-        create_dir_all(&out_dir).unwrap();
+        remove_and_create_dir_all(&out_dir);
 
         let proc_res = self.document(&out_dir);
         if !proc_res.status.success() {
@@ -2986,9 +2986,7 @@ impl<'test> TestCx<'test> {
         let suffix =
             self.safe_revision().map_or("nightly".into(), |path| path.to_owned() + "-nightly");
         let compare_dir = output_base_dir(self.config, self.testpaths, Some(&suffix));
-        // Don't give an error if the directory didn't already exist
-        let _ = fs::remove_dir_all(&compare_dir);
-        create_dir_all(&compare_dir).unwrap();
+        remove_and_create_dir_all(&compare_dir);
 
         // We need to create a new struct for the lifetimes on `config` to work.
         let new_rustdoc = TestCx {
@@ -3137,8 +3135,7 @@ impl<'test> TestCx<'test> {
         assert!(self.revision.is_none(), "revisions not relevant here");
 
         let out_dir = self.output_base_dir();
-        let _ = fs::remove_dir_all(&out_dir);
-        create_dir_all(&out_dir).unwrap();
+        remove_and_create_dir_all(&out_dir);
 
         let proc_res = self.document(&out_dir);
         if !proc_res.status.success() {
diff --git a/src/tools/rustfmt/src/expr.rs b/src/tools/rustfmt/src/expr.rs
index c500b30b998..053afcc52d4 100644
--- a/src/tools/rustfmt/src/expr.rs
+++ b/src/tools/rustfmt/src/expr.rs
@@ -3,7 +3,7 @@ use std::cmp::min;
 
 use itertools::Itertools;
 use rustc_ast::token::{Delimiter, Lit, LitKind};
-use rustc_ast::{ast, ptr, token, ForLoopKind};
+use rustc_ast::{ast, ptr, token, ForLoopKind, MatchKind};
 use rustc_span::{BytePos, Span};
 
 use crate::chains::rewrite_chain;
@@ -170,8 +170,8 @@ pub(crate) fn format_expr(
                 }
             }
         }
-        ast::ExprKind::Match(ref cond, ref arms) => {
-            rewrite_match(context, cond, arms, shape, expr.span, &expr.attrs)
+        ast::ExprKind::Match(ref cond, ref arms, kind) => {
+            rewrite_match(context, cond, arms, shape, expr.span, &expr.attrs, kind)
         }
         ast::ExprKind::Path(ref qself, ref path) => {
             rewrite_path(context, PathContext::Expr, qself, path, shape)
@@ -625,7 +625,7 @@ pub(crate) fn rewrite_cond(
     shape: Shape,
 ) -> Option<String> {
     match expr.kind {
-        ast::ExprKind::Match(ref cond, _) => {
+        ast::ExprKind::Match(ref cond, _, MatchKind::Prefix) => {
             // `match `cond` {`
             let cond_shape = match context.config.indent_style() {
                 IndentStyle::Visual => shape.shrink_left(6).and_then(|s| s.sub_width(2))?,
diff --git a/src/tools/rustfmt/src/matches.rs b/src/tools/rustfmt/src/matches.rs
index 5a00984d4c0..e68903c8715 100644
--- a/src/tools/rustfmt/src/matches.rs
+++ b/src/tools/rustfmt/src/matches.rs
@@ -2,7 +2,7 @@
 
 use std::iter::repeat;
 
-use rustc_ast::{ast, ptr};
+use rustc_ast::{ast, ptr, MatchKind};
 use rustc_span::{BytePos, Span};
 
 use crate::comment::{combine_strs_with_missing_comments, rewrite_comment};
@@ -72,6 +72,7 @@ pub(crate) fn rewrite_match(
     shape: Shape,
     span: Span,
     attrs: &[ast::Attribute],
+    match_kind: MatchKind,
 ) -> Option<String> {
     // Do not take the rhs overhead from the upper expressions into account
     // when rewriting match condition.
@@ -131,15 +132,27 @@ pub(crate) fn rewrite_match(
         }
     } else {
         let span_after_cond = mk_sp(cond.span.hi(), span.hi());
-        Some(format!(
-            "match {}{}{{\n{}{}{}\n{}}}",
-            cond_str,
-            block_sep,
-            inner_attrs_str,
-            nested_indent_str,
-            rewrite_match_arms(context, arms, shape, span_after_cond, open_brace_pos)?,
-            shape.indent.to_string(context.config),
-        ))
+
+        match match_kind {
+            MatchKind::Prefix => Some(format!(
+                "match {}{}{{\n{}{}{}\n{}}}",
+                cond_str,
+                block_sep,
+                inner_attrs_str,
+                nested_indent_str,
+                rewrite_match_arms(context, arms, shape, span_after_cond, open_brace_pos)?,
+                shape.indent.to_string(context.config),
+            )),
+            MatchKind::Postfix => Some(format!(
+                "{}.match{}{{\n{}{}{}\n{}}}",
+                cond_str,
+                block_sep,
+                inner_attrs_str,
+                nested_indent_str,
+                rewrite_match_arms(context, arms, shape, span_after_cond, open_brace_pos)?,
+                shape.indent.to_string(context.config),
+            )),
+        }
     }
 }
 
diff --git a/src/tools/rustfmt/src/patterns.rs b/src/tools/rustfmt/src/patterns.rs
index 7f576279432..47b48468a24 100644
--- a/src/tools/rustfmt/src/patterns.rs
+++ b/src/tools/rustfmt/src/patterns.rs
@@ -55,9 +55,10 @@ fn is_short_pattern_inner(pat: &ast::Pat) -> bool {
         ast::PatKind::TupleStruct(_, ref path, ref subpats) => {
             path.segments.len() <= 1 && subpats.len() <= 1
         }
-        ast::PatKind::Box(ref p) | ast::PatKind::Ref(ref p, _) | ast::PatKind::Paren(ref p) => {
-            is_short_pattern_inner(&*p)
-        }
+        ast::PatKind::Box(ref p)
+        | PatKind::Deref(ref p)
+        | ast::PatKind::Ref(ref p, _)
+        | ast::PatKind::Paren(ref p) => is_short_pattern_inner(&*p),
         PatKind::Or(ref pats) => pats.iter().all(|p| is_short_pattern_inner(p)),
     }
 }
@@ -277,6 +278,7 @@ impl Rewrite for Pat {
                 .rewrite(context, shape.offset_left(1)?.sub_width(1)?)
                 .map(|inner_pat| format!("({})", inner_pat)),
             PatKind::Err(_) => None,
+            PatKind::Deref(_) => None,
         }
     }
 }
diff --git a/src/tools/rustfmt/tests/source/postfix-match/pf-match.rs b/src/tools/rustfmt/tests/source/postfix-match/pf-match.rs
new file mode 100644
index 00000000000..b2366723631
--- /dev/null
+++ b/src/tools/rustfmt/tests/source/postfix-match/pf-match.rs
@@ -0,0 +1,20 @@
+#![feature(postfix_match)]
+
+fn main() {
+    let val = Some(42);
+
+    val.match {
+        Some(_) => 2,
+        _ => 1
+    };
+
+    Some(2).match {
+        Some(_) => true,
+        None => false
+    }.match {
+        false => "ferris is cute",
+        true => "I turn cats in to petted cats",
+    }.match {
+        _ => (),
+    }
+}
\ No newline at end of file
diff --git a/src/tools/rustfmt/tests/target/postfix-match/pf-match.rs b/src/tools/rustfmt/tests/target/postfix-match/pf-match.rs
new file mode 100644
index 00000000000..f439f272623
--- /dev/null
+++ b/src/tools/rustfmt/tests/target/postfix-match/pf-match.rs
@@ -0,0 +1,20 @@
+#![feature(postfix_match)]
+
+fn main() {
+    let val = Some(42);
+
+    val.match {
+        Some(_) => 2,
+        _ => 1,
+    };
+
+    Some(2).match {
+        Some(_) => true,
+        None => false,
+    }.match {
+        false => "ferris is cute",
+        true => "I turn cats in to petted cats",
+    }.match {
+        _ => (),
+    }
+}
diff --git a/src/tools/tidy/src/ui_tests.rs b/src/tools/tidy/src/ui_tests.rs
index 22927cffd1b..fa24447f699 100644
--- a/src/tools/tidy/src/ui_tests.rs
+++ b/src/tools/tidy/src/ui_tests.rs
@@ -183,9 +183,10 @@ pub fn check(root_path: &Path, bless: bool, bad: &mut bool) {
         }
     });
 
-    // if an excluded file is renamed, it must be removed from this list
+    // if there are any file names remaining, they were moved on the fs.
+    // our data must remain up to date, so it must be removed from issues.txt
     // do this automatically on bless, otherwise issue a tidy error
-    if bless {
+    if bless && !remaining_issue_names.is_empty() {
         let issues_txt_header = r#"
 /*
 ============================================================
diff --git a/tests/assembly/option-nonzero-eq.rs b/tests/assembly/option-nonzero-eq.rs
deleted file mode 100644
index b04cf63fd78..00000000000
--- a/tests/assembly/option-nonzero-eq.rs
+++ /dev/null
@@ -1,27 +0,0 @@
-//@ revisions: WIN LIN
-//@ [WIN] only-windows
-//@ [LIN] only-linux
-//@ assembly-output: emit-asm
-//@ compile-flags: --crate-type=lib -O -C llvm-args=-x86-asm-syntax=intel
-//@ only-x86_64
-//@ ignore-sgx
-
-use std::cmp::Ordering;
-
-// CHECK-lABEL: ordering_eq:
-#[no_mangle]
-pub fn ordering_eq(l: Option<Ordering>, r: Option<Ordering>) -> bool {
-    // Linux (System V): first two arguments are rdi then rsi
-    // Windows: first two arguments are rcx then rdx
-    // Both use rax for the return value.
-
-    // CHECK-NOT: mov
-    // CHECK-NOT: test
-    // CHECK-NOT: cmp
-
-    // LIN: cmp dil, sil
-    // WIN: cmp cl, dl
-    // CHECK-NEXT: sete al
-    // CHECK-NEXT: ret
-    l == r
-}
diff --git a/tests/assembly/targets/targets-elf.rs b/tests/assembly/targets/targets-elf.rs
index bda77b5f09b..3563aec6d80 100644
--- a/tests/assembly/targets/targets-elf.rs
+++ b/tests/assembly/targets/targets-elf.rs
@@ -369,6 +369,9 @@
 //@ revisions: riscv32im_unknown_none_elf
 //@ [riscv32im_unknown_none_elf] compile-flags: --target riscv32im-unknown-none-elf
 //@ [riscv32im_unknown_none_elf] needs-llvm-components: riscv
+//@ revisions: riscv32ima_unknown_none_elf
+//@ [riscv32ima_unknown_none_elf] compile-flags: --target riscv32ima-unknown-none-elf
+//@ [riscv32ima_unknown_none_elf] needs-llvm-components: riscv
 //@ revisions: riscv32imac_esp_espidf
 //@ [riscv32imac_esp_espidf] compile-flags: --target riscv32imac-esp-espidf
 //@ [riscv32imac_esp_espidf] needs-llvm-components: riscv
diff --git a/tests/codegen/option-nonzero-eq.rs b/tests/codegen/option-niche-eq.rs
index f637b1aef97..8b8044e9b75 100644
--- a/tests/codegen/option-nonzero-eq.rs
+++ b/tests/codegen/option-niche-eq.rs
@@ -1,4 +1,5 @@
 //@ compile-flags: -O -Zmerge-functions=disabled
+//@ min-llvm-version: 18
 #![crate_type = "lib"]
 #![feature(generic_nonzero)]
 
@@ -7,9 +8,6 @@ use core::cmp::Ordering;
 use core::ptr::NonNull;
 use core::num::NonZero;
 
-// See also tests/assembly/option-nonzero-eq.rs, for cases with `assume`s in the
-// LLVM and thus don't optimize down clearly here, but do in assembly.
-
 // CHECK-lABEL: @non_zero_eq
 #[no_mangle]
 pub fn non_zero_eq(l: Option<NonZero<u32>>, r: Option<NonZero<u32>>) -> bool {
@@ -36,3 +34,42 @@ pub fn non_null_eq(l: Option<NonNull<u8>>, r: Option<NonNull<u8>>) -> bool {
     // CHECK-NEXT: ret i1
     l == r
 }
+
+// CHECK-lABEL: @ordering_eq
+#[no_mangle]
+pub fn ordering_eq(l: Option<Ordering>, r: Option<Ordering>) -> bool {
+    // CHECK: start:
+    // CHECK-NEXT: icmp eq i8
+    // CHECK-NEXT: ret i1
+    l == r
+}
+
+#[derive(PartialEq)]
+pub enum EnumWithNiche {
+    A,
+    B,
+    C,
+    D,
+    E,
+    F,
+    G,
+}
+
+// CHECK-lABEL: @niche_eq
+#[no_mangle]
+pub fn niche_eq(l: Option<EnumWithNiche>, r: Option<EnumWithNiche>) -> bool {
+    // CHECK: start:
+    // CHECK-NEXT: icmp eq i8
+    // CHECK-NEXT: ret i1
+    l == r
+}
+
+// FIXME: This should work too
+// // FIXME-CHECK-lABEL: @bool_eq
+// #[no_mangle]
+// pub fn bool_eq(l: Option<bool>, r: Option<bool>) -> bool {
+//     // FIXME-CHECK: start:
+//     // FIXME-CHECK-NEXT: icmp eq i8
+//     // FIXME-CHECK-NEXT: ret i1
+//     l == r
+// }
diff --git a/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-paths.rs b/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-paths.rs
index c5d8e0f22a2..ca781a99296 100644
--- a/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-paths.rs
+++ b/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-paths.rs
@@ -47,40 +47,42 @@ pub fn foo() where
     let _: Type4 = <Foo>::bar;
 }
 
-pub fn foo1(_: Type1) { }
+// Force arguments to be passed by using a reference. Otherwise, they may end up PassMode::Ignore
+
+pub fn foo1(_: &Type1) { }
 // CHECK: define{{.*}}4foo1{{.*}}!type ![[TYPE1:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo2(_: Type1, _: Type1) { }
+pub fn foo2(_: &Type1, _: &Type1) { }
 // CHECK: define{{.*}}4foo2{{.*}}!type ![[TYPE2:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo3(_: Type1, _: Type1, _: Type1) { }
+pub fn foo3(_: &Type1, _: &Type1, _: &Type1) { }
 // CHECK: define{{.*}}4foo3{{.*}}!type ![[TYPE3:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo4(_: Type2) { }
+pub fn foo4(_: &Type2) { }
 // CHECK: define{{.*}}4foo4{{.*}}!type ![[TYPE4:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo5(_: Type2, _: Type2) { }
+pub fn foo5(_: &Type2, _: &Type2) { }
 // CHECK: define{{.*}}4foo5{{.*}}!type ![[TYPE5:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo6(_: Type2, _: Type2, _: Type2) { }
+pub fn foo6(_: &Type2, _: &Type2, _: &Type2) { }
 // CHECK: define{{.*}}4foo6{{.*}}!type ![[TYPE6:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo7(_: Type3) { }
+pub fn foo7(_: &Type3) { }
 // CHECK: define{{.*}}4foo7{{.*}}!type ![[TYPE7:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo8(_: Type3, _: Type3) { }
+pub fn foo8(_: &Type3, _: &Type3) { }
 // CHECK: define{{.*}}4foo8{{.*}}!type ![[TYPE8:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo9(_: Type3, _: Type3, _: Type3) { }
+pub fn foo9(_: &Type3, _: &Type3, _: &Type3) { }
 // CHECK: define{{.*}}4foo9{{.*}}!type ![[TYPE9:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo10(_: Type4) { }
+pub fn foo10(_: &Type4) { }
 // CHECK: define{{.*}}5foo10{{.*}}!type ![[TYPE10:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo11(_: Type4, _: Type4) { }
+pub fn foo11(_: &Type4, _: &Type4) { }
 // CHECK: define{{.*}}5foo11{{.*}}!type ![[TYPE11:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
-pub fn foo12(_: Type4, _: Type4, _: Type4) { }
+pub fn foo12(_: &Type4, _: &Type4, _: &Type4) { }
 // CHECK: define{{.*}}5foo12{{.*}}!type ![[TYPE12:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
 
-// CHECK: ![[TYPE1]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NvNFNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo10{{[{}][{}]}}extern{{[}][}]}}3barE"}
-// CHECK: ![[TYPE2]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NvNFNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo10{{[{}][{}]}}extern{{[}][}]}}3barS_E"}
-// CHECK: ![[TYPE3]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NvNFNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo10{{[{}][{}]}}extern{{[}][}]}}3barS_S_E"}
-// CHECK: ![[TYPE4]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NtNCNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo11{{[{}][{}]}}closure{{[}][}]}}3FooE"}
-// CHECK: ![[TYPE5]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NtNCNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo11{{[{}][{}]}}closure{{[}][}]}}3FooS_E"}
-// CHECK: ![[TYPE6]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NtNCNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo11{{[{}][{}]}}closure{{[}][}]}}3FooS_S_E"}
-// CHECK: ![[TYPE7]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NtNkNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo12{{[{}][{}]}}constant{{[}][}]}}3FooE"}
-// CHECK: ![[TYPE8]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NtNkNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo12{{[{}][{}]}}constant{{[}][}]}}3FooS_E"}
-// CHECK: ![[TYPE9]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NtNkNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo12{{[{}][{}]}}constant{{[}][}]}}3FooS_S_E"}
-// CHECK: ![[TYPE10]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NvNINvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo8{{[{}][{}]}}impl{{[}][}]}}3barE"}
-// CHECK: ![[TYPE11]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NvNINvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo8{{[{}][{}]}}impl{{[}][}]}}3barS_E"}
-// CHECK: ![[TYPE12]] = !{i64 0, !"_ZTSFvu{{[0-9]+}}NvNINvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo8{{[{}][{}]}}impl{{[}][}]}}3barS_S_E"}
+// CHECK: ![[TYPE1]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NvNFNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo10{{[{}][{}]}}extern{{[}][}]}}3barEE"}
+// CHECK: ![[TYPE2]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NvNFNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo10{{[{}][{}]}}extern{{[}][}]}}3barES0_E"}
+// CHECK: ![[TYPE3]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NvNFNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo10{{[{}][{}]}}extern{{[}][}]}}3barES0_S0_E"}
+// CHECK: ![[TYPE4]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NtNCNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo11{{[{}][{}]}}closure{{[}][}]}}3FooEE"}
+// CHECK: ![[TYPE5]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NtNCNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo11{{[{}][{}]}}closure{{[}][}]}}3FooES0_E"}
+// CHECK: ![[TYPE6]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NtNCNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo11{{[{}][{}]}}closure{{[}][}]}}3FooES0_S0_E"}
+// CHECK: ![[TYPE7]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NtNkNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo12{{[{}][{}]}}constant{{[}][}]}}3FooEE"}
+// CHECK: ![[TYPE8]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NtNkNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo12{{[{}][{}]}}constant{{[}][}]}}3FooES0_E"}
+// CHECK: ![[TYPE9]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NtNkNvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo12{{[{}][{}]}}constant{{[}][}]}}3FooES0_S0_E"}
+// CHECK: ![[TYPE10]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NvNINvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo8{{[{}][{}]}}impl{{[}][}]}}3barEE"}
+// CHECK: ![[TYPE11]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NvNINvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo8{{[{}][{}]}}impl{{[}][}]}}3barES0_E"}
+// CHECK: ![[TYPE12]] = !{i64 0, !"_ZTSFvu3refIu{{[0-9]+}}NvNINvC{{[[:print:]]+}}_{{[[:print:]]+}}3foo8{{[{}][{}]}}impl{{[}][}]}}3barES0_S0_E"}
diff --git a/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-primitive-types.rs b/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-primitive-types.rs
index 3a1a09150ea..38f507856bd 100644
--- a/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-primitive-types.rs
+++ b/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-primitive-types.rs
@@ -12,9 +12,9 @@ use core::ffi::*;
 pub fn foo1(_: ()) { }
 // CHECK: define{{.*}}4foo1{{.*}}!type ![[TYPE1:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
 pub fn foo2(_: (), _: c_void) { }
-// CHECK: define{{.*}}4foo2{{.*}}!type ![[TYPE2:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
+// CHECK: define{{.*}}4foo2{{.*}}!type ![[TYPE1:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
 pub fn foo3(_: (), _: c_void, _: c_void) { }
-// CHECK: define{{.*}}4foo3{{.*}}!type ![[TYPE3:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
+// CHECK: define{{.*}}4foo3{{.*}}!type ![[TYPE2:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
 pub fn foo4(_: *mut ()) { }
 // CHECK: define{{.*}}4foo4{{.*}}!type ![[TYPE4:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
 pub fn foo5(_: *mut (), _: *mut c_void) { }
@@ -131,8 +131,6 @@ pub fn foo60(_: &str, _: &str, _: &str) { }
 // CHECK: define{{.*}}5foo60{{.*}}!type ![[TYPE60:[0-9]+]] !type !{{[0-9]+}} !type !{{[0-9]+}} !type !{{[0-9]+}}
 
 // CHECK: ![[TYPE1]] = !{i64 0, !"_ZTSFvvE"}
-// CHECK: ![[TYPE2]] = !{i64 0, !"_ZTSFvvvE"}
-// CHECK: ![[TYPE3]] = !{i64 0, !"_ZTSFvvvvE"}
 // CHECK: ![[TYPE4]] = !{i64 0, !"_ZTSFvPvE"}
 // CHECK: ![[TYPE5]] = !{i64 0, !"_ZTSFvPvS_E"}
 // CHECK: ![[TYPE6]] = !{i64 0, !"_ZTSFvPvS_S_E"}
diff --git a/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-repr-transparent-types.rs b/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-repr-transparent-types.rs
index 0deda029c4b..6f47f5e3355 100644
--- a/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-repr-transparent-types.rs
+++ b/tests/codegen/sanitizer/cfi/emit-type-metadata-id-itanium-cxx-abi-repr-transparent-types.rs
@@ -28,7 +28,7 @@ pub struct Type2<'a> {
     member3: &'a Type2<'a>,
 }
 
-pub struct Bar;
+pub struct Bar(i32);
 
 // repr(transparent) user-defined generic type
 #[repr(transparent)]
diff --git a/tests/codegen/sanitizer/cfi/normalize-integers.rs b/tests/codegen/sanitizer/cfi/normalize-integers.rs
index 210814eb9ae..801ed312be5 100644
--- a/tests/codegen/sanitizer/cfi/normalize-integers.rs
+++ b/tests/codegen/sanitizer/cfi/normalize-integers.rs
@@ -41,6 +41,6 @@ pub fn foo11(_: (), _: usize, _: usize, _: usize) { }
 // CHECK: ![[TYPE6]] = !{i64 0, !"_ZTSFv{{u3i16|u3i32|u3i64|u4i128}}E.normalized"}
 // CHECK: ![[TYPE7]] = !{i64 0, !"_ZTSFv{{u3i16|u3i32|u3i64|u4i128}}S_E.normalized"}
 // CHECK: ![[TYPE8]] = !{i64 0, !"_ZTSFv{{u3i16|u3i32|u3i64|u4i128}}S_S_E.normalized"}
-// CHECK: ![[TYPE9]] = !{i64 0, !"_ZTSFvv{{u3u16|u3u32|u3u64|u4u128}}E.normalized"}
-// CHECK: ![[TYPE10]] = !{i64 0, !"_ZTSFvv{{u3u16|u3u32|u3u64|u4u128}}S_E.normalized"}
-// CHECK: ![[TYPE11]] = !{i64 0, !"_ZTSFvv{{u3u16|u3u32|u3u64|u4u128}}S_S_E.normalized"}
+// CHECK: ![[TYPE9]] = !{i64 0, !"_ZTSFv{{u3u16|u3u32|u3u64|u4u128}}E.normalized"}
+// CHECK: ![[TYPE10]] = !{i64 0, !"_ZTSFv{{u3u16|u3u32|u3u64|u4u128}}S_E.normalized"}
+// CHECK: ![[TYPE11]] = !{i64 0, !"_ZTSFv{{u3u16|u3u32|u3u64|u4u128}}S_S_E.normalized"}
diff --git a/tests/coverage/let_else_loop.cov-map b/tests/coverage/let_else_loop.cov-map
new file mode 100644
index 00000000000..b0cee300522
--- /dev/null
+++ b/tests/coverage/let_else_loop.cov-map
@@ -0,0 +1,30 @@
+Function name: let_else_loop::_if (unused)
+Raw bytes (19): 0x[01, 01, 00, 03, 00, 16, 01, 01, 0c, 00, 02, 09, 00, 10, 00, 02, 09, 00, 10]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 3
+- Code(Zero) at (prev + 22, 1) to (start + 1, 12)
+- Code(Zero) at (prev + 2, 9) to (start + 0, 16)
+- Code(Zero) at (prev + 2, 9) to (start + 0, 16)
+
+Function name: let_else_loop::_loop_either_way (unused)
+Raw bytes (19): 0x[01, 01, 00, 03, 00, 0f, 01, 01, 14, 00, 01, 1c, 00, 23, 00, 01, 05, 00, 0c]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 3
+- Code(Zero) at (prev + 15, 1) to (start + 1, 20)
+- Code(Zero) at (prev + 1, 28) to (start + 0, 35)
+- Code(Zero) at (prev + 1, 5) to (start + 0, 12)
+
+Function name: let_else_loop::loopy
+Raw bytes (19): 0x[01, 01, 00, 03, 01, 09, 01, 01, 14, 00, 01, 1c, 00, 23, 05, 01, 01, 00, 02]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 3
+- Code(Counter(0)) at (prev + 9, 1) to (start + 1, 20)
+- Code(Zero) at (prev + 1, 28) to (start + 0, 35)
+- Code(Counter(1)) at (prev + 1, 1) to (start + 0, 2)
+
diff --git a/tests/coverage/let_else_loop.coverage b/tests/coverage/let_else_loop.coverage
new file mode 100644
index 00000000000..d193c8ca1b5
--- /dev/null
+++ b/tests/coverage/let_else_loop.coverage
@@ -0,0 +1,35 @@
+   LL|       |#![feature(coverage_attribute)]
+   LL|       |//@ edition: 2021
+   LL|       |
+   LL|       |// Regression test for <https://github.com/rust-lang/rust/issues/122738>.
+   LL|       |// These code patterns should not trigger an ICE when allocating a physical
+   LL|       |// counter to a node and also one of its in-edges, because that is allowed
+   LL|       |// when the node contains a tight loop to itself.
+   LL|       |
+   LL|      1|fn loopy(cond: bool) {
+   LL|      1|    let true = cond else { loop {} };
+                                         ^0
+   LL|      1|}
+   LL|       |
+   LL|       |// Variant that also has `loop {}` on the success path.
+   LL|       |// This isn't needed to catch the original ICE, but might help detect regressions.
+   LL|      0|fn _loop_either_way(cond: bool) {
+   LL|      0|    let true = cond else { loop {} };
+   LL|      0|    loop {}
+   LL|       |}
+   LL|       |
+   LL|       |// Variant using regular `if` instead of let-else.
+   LL|       |// This doesn't trigger the original ICE, but might help detect regressions.
+   LL|      0|fn _if(cond: bool) {
+   LL|      0|    if cond {
+   LL|      0|        loop {}
+   LL|       |    } else {
+   LL|      0|        loop {}
+   LL|       |    }
+   LL|       |}
+   LL|       |
+   LL|       |#[coverage(off)]
+   LL|       |fn main() {
+   LL|       |    loopy(true);
+   LL|       |}
+
diff --git a/tests/coverage/let_else_loop.rs b/tests/coverage/let_else_loop.rs
new file mode 100644
index 00000000000..12e0aeabcab
--- /dev/null
+++ b/tests/coverage/let_else_loop.rs
@@ -0,0 +1,33 @@
+#![feature(coverage_attribute)]
+//@ edition: 2021
+
+// Regression test for <https://github.com/rust-lang/rust/issues/122738>.
+// These code patterns should not trigger an ICE when allocating a physical
+// counter to a node and also one of its in-edges, because that is allowed
+// when the node contains a tight loop to itself.
+
+fn loopy(cond: bool) {
+    let true = cond else { loop {} };
+}
+
+// Variant that also has `loop {}` on the success path.
+// This isn't needed to catch the original ICE, but might help detect regressions.
+fn _loop_either_way(cond: bool) {
+    let true = cond else { loop {} };
+    loop {}
+}
+
+// Variant using regular `if` instead of let-else.
+// This doesn't trigger the original ICE, but might help detect regressions.
+fn _if(cond: bool) {
+    if cond {
+        loop {}
+    } else {
+        loop {}
+    }
+}
+
+#[coverage(off)]
+fn main() {
+    loopy(true);
+}
diff --git a/tests/mir-opt/instrument_coverage_cleanup.main.CleanupPostBorrowck.diff b/tests/mir-opt/instrument_coverage_cleanup.main.CleanupPostBorrowck.diff
new file mode 100644
index 00000000000..ff65ca77039
--- /dev/null
+++ b/tests/mir-opt/instrument_coverage_cleanup.main.CleanupPostBorrowck.diff
@@ -0,0 +1,56 @@
+- // MIR for `main` before CleanupPostBorrowck
++ // MIR for `main` after CleanupPostBorrowck
+  
+  fn main() -> () {
+      let mut _0: ();
+      let mut _1: bool;
+  
+      coverage branch { true: BlockMarkerId(0), false: BlockMarkerId(1) } => /the/src/instrument_coverage_cleanup.rs:15:8: 15:36 (#0)
+  
+      coverage ExpressionId(0) => Expression { lhs: Counter(0), op: Subtract, rhs: Counter(1) };
+      coverage ExpressionId(1) => Expression { lhs: Counter(1), op: Add, rhs: Expression(0) };
+      coverage Code(Counter(0)) => /the/src/instrument_coverage_cleanup.rs:14:1 - 15:36;
+      coverage Code(Expression(0)) => /the/src/instrument_coverage_cleanup.rs:15:37 - 15:39;
+      coverage Code(Counter(1)) => /the/src/instrument_coverage_cleanup.rs:15:39 - 15:40;
+      coverage Code(Expression(1)) => /the/src/instrument_coverage_cleanup.rs:16:1 - 16:2;
+      coverage Branch { true_term: Expression(0), false_term: Counter(1) } => /the/src/instrument_coverage_cleanup.rs:15:8 - 15:36;
+  
+      bb0: {
+          Coverage::CounterIncrement(0);
+-         Coverage::SpanMarker;
++         nop;
+          StorageLive(_1);
+          _1 = std::hint::black_box::<bool>(const true) -> [return: bb1, unwind: bb5];
+      }
+  
+      bb1: {
+          switchInt(move _1) -> [0: bb3, otherwise: bb2];
+      }
+  
+      bb2: {
+          Coverage::CounterIncrement(1);
+-         Coverage::BlockMarker(1);
++         nop;
+          _0 = const ();
+          goto -> bb4;
+      }
+  
+      bb3: {
+          Coverage::ExpressionUsed(0);
+-         Coverage::BlockMarker(0);
++         nop;
+          _0 = const ();
+          goto -> bb4;
+      }
+  
+      bb4: {
+          Coverage::ExpressionUsed(1);
+          StorageDead(_1);
+          return;
+      }
+  
+      bb5 (cleanup): {
+          resume;
+      }
+  }
+  
diff --git a/tests/mir-opt/instrument_coverage_cleanup.main.InstrumentCoverage.diff b/tests/mir-opt/instrument_coverage_cleanup.main.InstrumentCoverage.diff
new file mode 100644
index 00000000000..8757559149a
--- /dev/null
+++ b/tests/mir-opt/instrument_coverage_cleanup.main.InstrumentCoverage.diff
@@ -0,0 +1,53 @@
+- // MIR for `main` before InstrumentCoverage
++ // MIR for `main` after InstrumentCoverage
+  
+  fn main() -> () {
+      let mut _0: ();
+      let mut _1: bool;
+  
+      coverage branch { true: BlockMarkerId(0), false: BlockMarkerId(1) } => /the/src/instrument_coverage_cleanup.rs:15:8: 15:36 (#0)
+  
++     coverage ExpressionId(0) => Expression { lhs: Counter(0), op: Subtract, rhs: Counter(1) };
++     coverage ExpressionId(1) => Expression { lhs: Counter(1), op: Add, rhs: Expression(0) };
++     coverage Code(Counter(0)) => /the/src/instrument_coverage_cleanup.rs:14:1 - 15:36;
++     coverage Code(Expression(0)) => /the/src/instrument_coverage_cleanup.rs:15:37 - 15:39;
++     coverage Code(Counter(1)) => /the/src/instrument_coverage_cleanup.rs:15:39 - 15:40;
++     coverage Code(Expression(1)) => /the/src/instrument_coverage_cleanup.rs:16:1 - 16:2;
++     coverage Branch { true_term: Expression(0), false_term: Counter(1) } => /the/src/instrument_coverage_cleanup.rs:15:8 - 15:36;
++ 
+      bb0: {
++         Coverage::CounterIncrement(0);
+          Coverage::SpanMarker;
+          StorageLive(_1);
+          _1 = std::hint::black_box::<bool>(const true) -> [return: bb1, unwind: bb5];
+      }
+  
+      bb1: {
+          switchInt(move _1) -> [0: bb3, otherwise: bb2];
+      }
+  
+      bb2: {
++         Coverage::CounterIncrement(1);
+          Coverage::BlockMarker(1);
+          _0 = const ();
+          goto -> bb4;
+      }
+  
+      bb3: {
++         Coverage::ExpressionUsed(0);
+          Coverage::BlockMarker(0);
+          _0 = const ();
+          goto -> bb4;
+      }
+  
+      bb4: {
++         Coverage::ExpressionUsed(1);
+          StorageDead(_1);
+          return;
+      }
+  
+      bb5 (cleanup): {
+          resume;
+      }
+  }
+  
diff --git a/tests/mir-opt/instrument_coverage_cleanup.rs b/tests/mir-opt/instrument_coverage_cleanup.rs
new file mode 100644
index 00000000000..8a2fd67139b
--- /dev/null
+++ b/tests/mir-opt/instrument_coverage_cleanup.rs
@@ -0,0 +1,22 @@
+// Test that CleanupPostBorrowck cleans up the marker statements that are
+// inserted during MIR building (after InstrumentCoverage is done with them),
+// but leaves the statements that were added by InstrumentCoverage.
+//
+// Removed statement kinds: BlockMarker, SpanMarker
+// Retained statement kinds: CounterIncrement, ExpressionUsed
+
+//@ unit-test: InstrumentCoverage
+//@ compile-flags: -Cinstrument-coverage -Zcoverage-options=branch -Zno-profiler-runtime
+//@ compile-flags: --remap-path-prefix={{src-base}}=/the/src
+
+// EMIT_MIR instrument_coverage_cleanup.main.InstrumentCoverage.diff
+// EMIT_MIR instrument_coverage_cleanup.main.CleanupPostBorrowck.diff
+fn main() {
+    if !core::hint::black_box(true) {}
+}
+
+// CHECK-NOT: Coverage::BlockMarker
+// CHECK-NOT: Coverage::SpanMarker
+// CHECK:     Coverage::CounterIncrement
+// CHECK-NOT: Coverage::BlockMarker
+// CHECK-NOT: Coverage::SpanMarker
diff --git a/tests/pretty/postfix-match.rs b/tests/pretty/postfix-match.rs
new file mode 100644
index 00000000000..5bb54e15275
--- /dev/null
+++ b/tests/pretty/postfix-match.rs
@@ -0,0 +1,21 @@
+#![feature(postfix_match)]
+
+fn main() {
+    let val = Some(42);
+
+    val.match {
+        Some(_) => 2,
+        _ => 1
+    };
+
+
+    Some(2).match {
+        Some(_) => true,
+        None => false
+    }.match {
+        false => "ferris is cute",
+        true => "I turn cats in to petted cats",
+    }.match {
+        _ => (),
+    }
+}
diff --git a/tests/run-make-fulldeps/obtain-borrowck/driver.rs b/tests/run-make-fulldeps/obtain-borrowck/driver.rs
index 2e3bf70e144..e67ec8690f8 100644
--- a/tests/run-make-fulldeps/obtain-borrowck/driver.rs
+++ b/tests/run-make-fulldeps/obtain-borrowck/driver.rs
@@ -68,7 +68,7 @@ impl rustc_driver::Callbacks for CompilerCalls {
             let mut bodies = Vec::new();
 
             let crate_items = tcx.hir_crate_items(());
-            for id in crate_items.items() {
+            for id in crate_items.free_items() {
                 if matches!(tcx.def_kind(id.owner_id), DefKind::Fn) {
                     bodies.push(id.owner_id);
                 }
diff --git a/tests/rustdoc-ui/invalid_associated_const.rs b/tests/rustdoc-ui/invalid_associated_const.rs
index 6ab8c36f740..6f211a383a6 100644
--- a/tests/rustdoc-ui/invalid_associated_const.rs
+++ b/tests/rustdoc-ui/invalid_associated_const.rs
@@ -3,6 +3,7 @@
 trait T {
     type A: S<C<X = 0i32> = 34>;
     //~^ ERROR associated type bindings are not allowed here
+    //~| ERROR associated type bindings are not allowed here
 }
 
 trait S {
diff --git a/tests/rustdoc-ui/invalid_associated_const.stderr b/tests/rustdoc-ui/invalid_associated_const.stderr
index 9c6ae0f76c6..1eb6d2714e3 100644
--- a/tests/rustdoc-ui/invalid_associated_const.stderr
+++ b/tests/rustdoc-ui/invalid_associated_const.stderr
@@ -4,6 +4,14 @@ error[E0229]: associated type bindings are not allowed here
 LL |     type A: S<C<X = 0i32> = 34>;
    |                 ^^^^^^^^ associated type not allowed here
 
-error: aborting due to 1 previous error
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/invalid_associated_const.rs:4:17
+   |
+LL |     type A: S<C<X = 0i32> = 34>;
+   |                 ^^^^^^^^ associated type not allowed here
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/rustdoc-ui/issue-102467.rs b/tests/rustdoc-ui/issue-102467.rs
index bff876e41d6..a27e6156979 100644
--- a/tests/rustdoc-ui/issue-102467.rs
+++ b/tests/rustdoc-ui/issue-102467.rs
@@ -6,6 +6,7 @@
 trait T {
     type A: S<C<X = 0i32> = 34>;
     //~^ ERROR associated type bindings are not allowed here
+    //~| ERROR associated type bindings are not allowed here
 }
 
 trait S {
diff --git a/tests/rustdoc-ui/issue-102467.stderr b/tests/rustdoc-ui/issue-102467.stderr
index 4a769f94cf2..f54a50a4e19 100644
--- a/tests/rustdoc-ui/issue-102467.stderr
+++ b/tests/rustdoc-ui/issue-102467.stderr
@@ -4,6 +4,14 @@ error[E0229]: associated type bindings are not allowed here
 LL |     type A: S<C<X = 0i32> = 34>;
    |                 ^^^^^^^^ associated type not allowed here
 
-error: aborting due to 1 previous error
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/issue-102467.rs:7:17
+   |
+LL |     type A: S<C<X = 0i32> = 34>;
+   |                 ^^^^^^^^ associated type not allowed here
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/rustdoc-ui/issues/issue-96287.rs b/tests/rustdoc-ui/issues/issue-96287.rs
index 08cc7ef4c90..b490c2fc03f 100644
--- a/tests/rustdoc-ui/issues/issue-96287.rs
+++ b/tests/rustdoc-ui/issues/issue-96287.rs
@@ -6,6 +6,7 @@ pub trait TraitWithAssoc {
 
 pub type Foo<V> = impl Trait<V::Assoc>;
 //~^ ERROR
+//~| ERROR
 
 pub trait Trait<U> {}
 
diff --git a/tests/rustdoc-ui/issues/issue-96287.stderr b/tests/rustdoc-ui/issues/issue-96287.stderr
index 62d81534a98..9aba0332164 100644
--- a/tests/rustdoc-ui/issues/issue-96287.stderr
+++ b/tests/rustdoc-ui/issues/issue-96287.stderr
@@ -9,6 +9,18 @@ help: consider restricting type parameter `V`
 LL | pub type Foo<V: TraitWithAssoc> = impl Trait<V::Assoc>;
    |               ++++++++++++++++
 
-error: aborting due to 1 previous error
+error[E0220]: associated type `Assoc` not found for `V`
+  --> $DIR/issue-96287.rs:7:33
+   |
+LL | pub type Foo<V> = impl Trait<V::Assoc>;
+   |                                 ^^^^^ there is an associated type `Assoc` in the trait `TraitWithAssoc`
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: consider restricting type parameter `V`
+   |
+LL | pub type Foo<V: TraitWithAssoc> = impl Trait<V::Assoc>;
+   |               ++++++++++++++++
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs
index aaf16181030..06fd0a024f0 100644
--- a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs
+++ b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.rs
@@ -37,8 +37,19 @@ fn take2<P: Project<SELF = {}>>(_: P) {}
 
 trait Iface<'r> {
     //~^ NOTE the lifetime parameter `'r` is defined here
+    //~| NOTE the lifetime parameter `'r` is defined here
     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
     //~^ ERROR the type of the associated constant `K` must not depend on generic parameters
+    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
+    //~| NOTE its type must not depend on the lifetime parameter `'r`
+    //~| NOTE `K` has type `&'r [Self; Q]`
+    //~| ERROR the type of the associated constant `K` must not depend on `Self`
+    //~| NOTE its type must not depend on `Self`
+    //~| NOTE `K` has type `&'r [Self; Q]`
+    //~| ERROR the type of the associated constant `K` must not depend on generic parameters
+    //~| NOTE its type must not depend on the const parameter `Q`
+    //~| NOTE the const parameter `Q` is defined here
+    //~| NOTE `K` has type `&'r [Self; Q]`
     //~| NOTE its type must not depend on the lifetime parameter `'r`
     //~| NOTE `K` has type `&'r [Self; Q]`
     //~| ERROR the type of the associated constant `K` must not depend on `Self`
@@ -48,6 +59,9 @@ trait Iface<'r> {
     //~| NOTE its type must not depend on the const parameter `Q`
     //~| NOTE the const parameter `Q` is defined here
     //~| NOTE `K` has type `&'r [Self; Q]`
+    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+    //~| NOTE duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
     where
         Self: Sized + 'r;
 }
diff --git a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr
index 077ac6e7f93..6b7b714fff1 100644
--- a/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr
+++ b/tests/ui/associated-consts/assoc-const-eq-param-in-ty.stderr
@@ -44,18 +44,18 @@ LL | fn take2<P: Project<SELF = {}>>(_: P) {}
    = note: `SELF` has type `P`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:40:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:41:52
    |
 LL | trait Iface<'r> {
    |             -- the lifetime parameter `'r` is defined here
-LL |
+...
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                                                    ^ its type must not depend on the lifetime parameter `'r`
    |
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on `Self`
-  --> $DIR/assoc-const-eq-param-in-ty.rs:40:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:41:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                                                    ^ its type must not depend on `Self`
@@ -63,7 +63,7 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    = note: `K` has type `&'r [Self; Q]`
 
 error: the type of the associated constant `K` must not depend on generic parameters
-  --> $DIR/assoc-const-eq-param-in-ty.rs:40:52
+  --> $DIR/assoc-const-eq-param-in-ty.rs:41:52
    |
 LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |                      -                             ^ its type must not depend on the const parameter `Q`
@@ -72,5 +72,37 @@ LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
    |
    = note: `K` has type `&'r [Self; Q]`
 
-error: aborting due to 8 previous errors
+error: the type of the associated constant `K` must not depend on generic parameters
+  --> $DIR/assoc-const-eq-param-in-ty.rs:41:52
+   |
+LL | trait Iface<'r> {
+   |             -- the lifetime parameter `'r` is defined here
+...
+LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
+   |                                                    ^ its type must not depend on the lifetime parameter `'r`
+   |
+   = note: `K` has type `&'r [Self; Q]`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: the type of the associated constant `K` must not depend on `Self`
+  --> $DIR/assoc-const-eq-param-in-ty.rs:41:52
+   |
+LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
+   |                                                    ^ its type must not depend on `Self`
+   |
+   = note: `K` has type `&'r [Self; Q]`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: the type of the associated constant `K` must not depend on generic parameters
+  --> $DIR/assoc-const-eq-param-in-ty.rs:41:52
+   |
+LL |     type Assoc<const Q: usize>: Trait<'r, Self, Q, K = { loop {} }>
+   |                      -                             ^ its type must not depend on the const parameter `Q`
+   |                      |
+   |                      the const parameter `Q` is defined here
+   |
+   = note: `K` has type `&'r [Self; Q]`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 11 previous errors
 
diff --git a/tests/ui/associated-consts/issue-102335-const.rs b/tests/ui/associated-consts/issue-102335-const.rs
index f60cb92da7f..969c2c43b71 100644
--- a/tests/ui/associated-consts/issue-102335-const.rs
+++ b/tests/ui/associated-consts/issue-102335-const.rs
@@ -3,6 +3,7 @@
 trait T {
     type A: S<C<X = 0i32> = 34>;
     //~^ ERROR associated type bindings are not allowed here
+    //~| ERROR associated type bindings are not allowed here
 }
 
 trait S {
diff --git a/tests/ui/associated-consts/issue-102335-const.stderr b/tests/ui/associated-consts/issue-102335-const.stderr
index b69dfd51ea8..2a70425a3cc 100644
--- a/tests/ui/associated-consts/issue-102335-const.stderr
+++ b/tests/ui/associated-consts/issue-102335-const.stderr
@@ -4,6 +4,14 @@ error[E0229]: associated type bindings are not allowed here
 LL |     type A: S<C<X = 0i32> = 34>;
    |                 ^^^^^^^^ associated type not allowed here
 
-error: aborting due to 1 previous error
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/issue-102335-const.rs:4:17
+   |
+LL |     type A: S<C<X = 0i32> = 34>;
+   |                 ^^^^^^^^ associated type not allowed here
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/ui/associated-inherent-types/issue-109299-1.rs b/tests/ui/associated-inherent-types/issue-109299-1.rs
index b86e2e31e06..4546785f0b1 100644
--- a/tests/ui/associated-inherent-types/issue-109299-1.rs
+++ b/tests/ui/associated-inherent-types/issue-109299-1.rs
@@ -7,7 +7,9 @@ impl Lexer<i32> {
     type Cursor = ();
 }
 
-type X = impl for<T> Fn() -> Lexer<T>::Cursor; //~ ERROR associated type `Cursor` not found for `Lexer<T>` in the current scope
-//~^ ERROR: unconstrained opaque type
+type X = impl for<T> Fn() -> Lexer<T>::Cursor;
+//~^ ERROR associated type `Cursor` not found for `Lexer<T>` in the current scope
+//~| ERROR associated type `Cursor` not found for `Lexer<T>` in the current scope
+//~| ERROR: unconstrained opaque type
 
 fn main() {}
diff --git a/tests/ui/associated-inherent-types/issue-109299-1.stderr b/tests/ui/associated-inherent-types/issue-109299-1.stderr
index 5848fa4087d..07a00b6b9a9 100644
--- a/tests/ui/associated-inherent-types/issue-109299-1.stderr
+++ b/tests/ui/associated-inherent-types/issue-109299-1.stderr
@@ -10,6 +10,19 @@ LL | type X = impl for<T> Fn() -> Lexer<T>::Cursor;
    = note: the associated type was found for
            - `Lexer<i32>`
 
+error[E0220]: associated type `Cursor` not found for `Lexer<T>` in the current scope
+  --> $DIR/issue-109299-1.rs:10:40
+   |
+LL | struct Lexer<T>(T);
+   | --------------- associated item `Cursor` not found for this struct
+...
+LL | type X = impl for<T> Fn() -> Lexer<T>::Cursor;
+   |                                        ^^^^^^ associated item not found in `Lexer<T>`
+   |
+   = note: the associated type was found for
+           - `Lexer<i32>`
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error: unconstrained opaque type
   --> $DIR/issue-109299-1.rs:10:10
    |
@@ -18,6 +31,6 @@ LL | type X = impl for<T> Fn() -> Lexer<T>::Cursor;
    |
    = note: `X` must be used in combination with a concrete type within the same module
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid-2.rs b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid-2.rs
new file mode 100644
index 00000000000..1768b006622
--- /dev/null
+++ b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid-2.rs
@@ -0,0 +1,18 @@
+trait Id {
+    type This: ?Sized;
+}
+impl<T: ?Sized> Id for T {
+    type This = T;
+}
+
+trait Trait {
+    type Assoc: Id<This: Copy>;
+}
+
+// We can't see use the `T::Assoc::This: Copy` bound to prove `T::Assoc: Copy`
+fn foo<T: Trait>(x: T::Assoc) -> (T::Assoc, T::Assoc) {
+    (x, x)
+    //~^ ERROR use of moved value
+}
+
+fn main() {}
diff --git a/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid-2.stderr b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid-2.stderr
new file mode 100644
index 00000000000..cd0e026905c
--- /dev/null
+++ b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid-2.stderr
@@ -0,0 +1,13 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/cant-see-copy-bound-from-child-rigid-2.rs:14:9
+   |
+LL | fn foo<T: Trait>(x: T::Assoc) -> (T::Assoc, T::Assoc) {
+   |                  - move occurs because `x` has type `<T as Trait>::Assoc`, which does not implement the `Copy` trait
+LL |     (x, x)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.rs b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.rs
new file mode 100644
index 00000000000..6b3fd7e898d
--- /dev/null
+++ b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.rs
@@ -0,0 +1,18 @@
+trait Id {
+    type This: ?Sized;
+}
+
+trait Trait {
+    type Assoc: Id<This: Copy>;
+}
+
+// We can't see use the `T::Assoc::This: Copy` bound to prove `T::Assoc: Copy`
+fn foo<T: Trait>(x: T::Assoc) -> (T::Assoc, T::Assoc)
+where
+    T::Assoc: Id<This = T::Assoc>,
+{
+    (x, x)
+    //~^ ERROR use of moved value
+}
+
+fn main() {}
diff --git a/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.stderr b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.stderr
new file mode 100644
index 00000000000..3ed73918de3
--- /dev/null
+++ b/tests/ui/associated-type-bounds/cant-see-copy-bound-from-child-rigid.stderr
@@ -0,0 +1,14 @@
+error[E0382]: use of moved value: `x`
+  --> $DIR/cant-see-copy-bound-from-child-rigid.rs:14:9
+   |
+LL | fn foo<T: Trait>(x: T::Assoc) -> (T::Assoc, T::Assoc)
+   |                  - move occurs because `x` has type `<T as Trait>::Assoc`, which does not implement the `Copy` trait
+...
+LL |     (x, x)
+   |      -  ^ value used here after move
+   |      |
+   |      value moved here
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0382`.
diff --git a/tests/ui/associated-type-bounds/dont-imply-atb-in-closure-inference.rs b/tests/ui/associated-type-bounds/dont-imply-atb-in-closure-inference.rs
new file mode 100644
index 00000000000..fecb3b15338
--- /dev/null
+++ b/tests/ui/associated-type-bounds/dont-imply-atb-in-closure-inference.rs
@@ -0,0 +1,21 @@
+//@ check-pass
+
+#![feature(type_alias_impl_trait)]
+
+trait IsPtr {
+    type Assoc;
+}
+impl<T> IsPtr for T {
+    type Assoc = fn(i32);
+}
+
+type Tait = impl IsPtr<Assoc: Fn(i32)> + Fn(u32);
+
+fn hello()
+where
+    Tait:,
+{
+    let _: Tait = |x| {};
+}
+
+fn main() {}
diff --git a/tests/ui/associated-type-bounds/duplicate.rs b/tests/ui/associated-type-bounds/duplicate.rs
index 06a1993da72..2b4a01376d7 100644
--- a/tests/ui/associated-type-bounds/duplicate.rs
+++ b/tests/ui/associated-type-bounds/duplicate.rs
@@ -132,16 +132,19 @@ where
 
 fn FRPIT1() -> impl Iterator<Item: Copy, Item: Send> {
     //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+    //~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
     iter::empty()
     //~^ ERROR type annotations needed
 }
 fn FRPIT2() -> impl Iterator<Item: Copy, Item: Copy> {
     //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+    //~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
     iter::empty()
     //~^ ERROR type annotations needed
 }
 fn FRPIT3() -> impl Iterator<Item: 'static, Item: 'static> {
     //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+    //~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
     iter::empty()
     //~^ ERROR type annotations needed
 }
@@ -182,10 +185,13 @@ type ETAI3<T: Iterator<Item: 'static, Item: 'static>> = impl Copy;
 //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 type ETAI4 = impl Iterator<Item: Copy, Item: Send>;
 //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+//~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 type ETAI5 = impl Iterator<Item: Copy, Item: Copy>;
 //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+//~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 type ETAI6 = impl Iterator<Item: 'static, Item: 'static>;
 //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+//~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 
 trait TRI1<T: Iterator<Item: Copy, Item: Send>> {}
 //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
@@ -250,14 +256,17 @@ where
 trait TRA1 {
     type A: Iterator<Item: Copy, Item: Send>;
     //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+    //~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 }
 trait TRA2 {
     type A: Iterator<Item: Copy, Item: Copy>;
     //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+    //~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 }
 trait TRA3 {
     type A: Iterator<Item: 'static, Item: 'static>;
     //~^ ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
+    //~| ERROR the value of the associated type `Item` in trait `Iterator` is already specified [E0719]
 }
 
 fn main() {}
diff --git a/tests/ui/associated-type-bounds/duplicate.stderr b/tests/ui/associated-type-bounds/duplicate.stderr
index 2d298f0a013..cf4809991c3 100644
--- a/tests/ui/associated-type-bounds/duplicate.stderr
+++ b/tests/ui/associated-type-bounds/duplicate.stderr
@@ -198,8 +198,18 @@ LL | fn FRPIT1() -> impl Iterator<Item: Copy, Item: Send> {
    |                              |
    |                              `Item` bound here first
 
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:133:42
+   |
+LL | fn FRPIT1() -> impl Iterator<Item: Copy, Item: Send> {
+   |                              ----------  ^^^^^^^^^^ re-bound here
+   |                              |
+   |                              `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error[E0282]: type annotations needed
-  --> $DIR/duplicate.rs:135:5
+  --> $DIR/duplicate.rs:136:5
    |
 LL |     iter::empty()
    |     ^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `empty`
@@ -210,15 +220,25 @@ LL |     iter::empty::<T>()
    |                +++++
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:138:42
+  --> $DIR/duplicate.rs:139:42
+   |
+LL | fn FRPIT2() -> impl Iterator<Item: Copy, Item: Copy> {
+   |                              ----------  ^^^^^^^^^^ re-bound here
+   |                              |
+   |                              `Item` bound here first
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:139:42
    |
 LL | fn FRPIT2() -> impl Iterator<Item: Copy, Item: Copy> {
    |                              ----------  ^^^^^^^^^^ re-bound here
    |                              |
    |                              `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0282]: type annotations needed
-  --> $DIR/duplicate.rs:140:5
+  --> $DIR/duplicate.rs:142:5
    |
 LL |     iter::empty()
    |     ^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `empty`
@@ -229,15 +249,25 @@ LL |     iter::empty::<T>()
    |                +++++
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:143:45
+  --> $DIR/duplicate.rs:145:45
+   |
+LL | fn FRPIT3() -> impl Iterator<Item: 'static, Item: 'static> {
+   |                              -------------  ^^^^^^^^^^^^^ re-bound here
+   |                              |
+   |                              `Item` bound here first
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:145:45
    |
 LL | fn FRPIT3() -> impl Iterator<Item: 'static, Item: 'static> {
    |                              -------------  ^^^^^^^^^^^^^ re-bound here
    |                              |
    |                              `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0282]: type annotations needed
-  --> $DIR/duplicate.rs:145:5
+  --> $DIR/duplicate.rs:148:5
    |
 LL |     iter::empty()
    |     ^^^^^^^^^^^ cannot infer type of the type parameter `T` declared on the function `empty`
@@ -248,7 +278,7 @@ LL |     iter::empty::<T>()
    |                +++++
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:148:40
+  --> $DIR/duplicate.rs:151:40
    |
 LL | fn FAPIT1(_: impl Iterator<Item: Copy, Item: Send>) {}
    |                            ----------  ^^^^^^^^^^ re-bound here
@@ -256,7 +286,7 @@ LL | fn FAPIT1(_: impl Iterator<Item: Copy, Item: Send>) {}
    |                            `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:150:40
+  --> $DIR/duplicate.rs:153:40
    |
 LL | fn FAPIT2(_: impl Iterator<Item: Copy, Item: Copy>) {}
    |                            ----------  ^^^^^^^^^^ re-bound here
@@ -264,7 +294,7 @@ LL | fn FAPIT2(_: impl Iterator<Item: Copy, Item: Copy>) {}
    |                            `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:152:43
+  --> $DIR/duplicate.rs:155:43
    |
 LL | fn FAPIT3(_: impl Iterator<Item: 'static, Item: 'static>) {}
    |                            -------------  ^^^^^^^^^^^^^ re-bound here
@@ -272,7 +302,7 @@ LL | fn FAPIT3(_: impl Iterator<Item: 'static, Item: 'static>) {}
    |                            `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:155:35
+  --> $DIR/duplicate.rs:158:35
    |
 LL | type TAI1<T: Iterator<Item: Copy, Item: Send>> = T;
    |                       ----------  ^^^^^^^^^^ re-bound here
@@ -280,7 +310,7 @@ LL | type TAI1<T: Iterator<Item: Copy, Item: Send>> = T;
    |                       `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:157:35
+  --> $DIR/duplicate.rs:160:35
    |
 LL | type TAI2<T: Iterator<Item: Copy, Item: Copy>> = T;
    |                       ----------  ^^^^^^^^^^ re-bound here
@@ -288,7 +318,7 @@ LL | type TAI2<T: Iterator<Item: Copy, Item: Copy>> = T;
    |                       `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:159:38
+  --> $DIR/duplicate.rs:162:38
    |
 LL | type TAI3<T: Iterator<Item: 'static, Item: 'static>> = T;
    |                       -------------  ^^^^^^^^^^^^^ re-bound here
@@ -296,7 +326,7 @@ LL | type TAI3<T: Iterator<Item: 'static, Item: 'static>> = T;
    |                       `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:163:29
+  --> $DIR/duplicate.rs:166:29
    |
 LL |     T: Iterator<Item: Copy, Item: Send>,
    |                 ----------  ^^^^^^^^^^ re-bound here
@@ -304,7 +334,7 @@ LL |     T: Iterator<Item: Copy, Item: Send>,
    |                 `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:168:29
+  --> $DIR/duplicate.rs:171:29
    |
 LL |     T: Iterator<Item: Copy, Item: Copy>,
    |                 ----------  ^^^^^^^^^^ re-bound here
@@ -312,7 +342,7 @@ LL |     T: Iterator<Item: Copy, Item: Copy>,
    |                 `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:173:32
+  --> $DIR/duplicate.rs:176:32
    |
 LL |     T: Iterator<Item: 'static, Item: 'static>,
    |                 -------------  ^^^^^^^^^^^^^ re-bound here
@@ -320,7 +350,7 @@ LL |     T: Iterator<Item: 'static, Item: 'static>,
    |                 `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:177:36
+  --> $DIR/duplicate.rs:180:36
    |
 LL | type ETAI1<T: Iterator<Item: Copy, Item: Send>> = impl Copy;
    |                        ----------  ^^^^^^^^^^ re-bound here
@@ -328,7 +358,7 @@ LL | type ETAI1<T: Iterator<Item: Copy, Item: Send>> = impl Copy;
    |                        `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:179:36
+  --> $DIR/duplicate.rs:182:36
    |
 LL | type ETAI2<T: Iterator<Item: Copy, Item: Copy>> = impl Copy;
    |                        ----------  ^^^^^^^^^^ re-bound here
@@ -336,7 +366,7 @@ LL | type ETAI2<T: Iterator<Item: Copy, Item: Copy>> = impl Copy;
    |                        `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:181:39
+  --> $DIR/duplicate.rs:184:39
    |
 LL | type ETAI3<T: Iterator<Item: 'static, Item: 'static>> = impl Copy;
    |                        -------------  ^^^^^^^^^^^^^ re-bound here
@@ -344,23 +374,43 @@ LL | type ETAI3<T: Iterator<Item: 'static, Item: 'static>> = impl Copy;
    |                        `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:183:40
+  --> $DIR/duplicate.rs:186:40
+   |
+LL | type ETAI4 = impl Iterator<Item: Copy, Item: Send>;
+   |                            ----------  ^^^^^^^^^^ re-bound here
+   |                            |
+   |                            `Item` bound here first
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:186:40
    |
 LL | type ETAI4 = impl Iterator<Item: Copy, Item: Send>;
    |                            ----------  ^^^^^^^^^^ re-bound here
    |                            |
    |                            `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:189:40
+   |
+LL | type ETAI5 = impl Iterator<Item: Copy, Item: Copy>;
+   |                            ----------  ^^^^^^^^^^ re-bound here
+   |                            |
+   |                            `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:185:40
+  --> $DIR/duplicate.rs:189:40
    |
 LL | type ETAI5 = impl Iterator<Item: Copy, Item: Copy>;
    |                            ----------  ^^^^^^^^^^ re-bound here
    |                            |
    |                            `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:187:43
+  --> $DIR/duplicate.rs:192:43
    |
 LL | type ETAI6 = impl Iterator<Item: 'static, Item: 'static>;
    |                            -------------  ^^^^^^^^^^^^^ re-bound here
@@ -368,7 +418,17 @@ LL | type ETAI6 = impl Iterator<Item: 'static, Item: 'static>;
    |                            `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:190:36
+  --> $DIR/duplicate.rs:192:43
+   |
+LL | type ETAI6 = impl Iterator<Item: 'static, Item: 'static>;
+   |                            -------------  ^^^^^^^^^^^^^ re-bound here
+   |                            |
+   |                            `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:196:36
    |
 LL | trait TRI1<T: Iterator<Item: Copy, Item: Send>> {}
    |                        ----------  ^^^^^^^^^^ re-bound here
@@ -376,7 +436,7 @@ LL | trait TRI1<T: Iterator<Item: Copy, Item: Send>> {}
    |                        `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:192:36
+  --> $DIR/duplicate.rs:198:36
    |
 LL | trait TRI2<T: Iterator<Item: Copy, Item: Copy>> {}
    |                        ----------  ^^^^^^^^^^ re-bound here
@@ -384,7 +444,7 @@ LL | trait TRI2<T: Iterator<Item: Copy, Item: Copy>> {}
    |                        `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:194:39
+  --> $DIR/duplicate.rs:200:39
    |
 LL | trait TRI3<T: Iterator<Item: 'static, Item: 'static>> {}
    |                        -------------  ^^^^^^^^^^^^^ re-bound here
@@ -392,7 +452,7 @@ LL | trait TRI3<T: Iterator<Item: 'static, Item: 'static>> {}
    |                        `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:196:34
+  --> $DIR/duplicate.rs:202:34
    |
 LL | trait TRS1: Iterator<Item: Copy, Item: Send> {}
    |                      ----------  ^^^^^^^^^^ re-bound here
@@ -400,7 +460,7 @@ LL | trait TRS1: Iterator<Item: Copy, Item: Send> {}
    |                      `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:196:34
+  --> $DIR/duplicate.rs:202:34
    |
 LL | trait TRS1: Iterator<Item: Copy, Item: Send> {}
    |                      ----------  ^^^^^^^^^^ re-bound here
@@ -410,7 +470,7 @@ LL | trait TRS1: Iterator<Item: Copy, Item: Send> {}
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:196:34
+  --> $DIR/duplicate.rs:202:34
    |
 LL | trait TRS1: Iterator<Item: Copy, Item: Send> {}
    |                      ----------  ^^^^^^^^^^ re-bound here
@@ -420,7 +480,7 @@ LL | trait TRS1: Iterator<Item: Copy, Item: Send> {}
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:200:34
+  --> $DIR/duplicate.rs:206:34
    |
 LL | trait TRS2: Iterator<Item: Copy, Item: Copy> {}
    |                      ----------  ^^^^^^^^^^ re-bound here
@@ -428,7 +488,7 @@ LL | trait TRS2: Iterator<Item: Copy, Item: Copy> {}
    |                      `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:200:34
+  --> $DIR/duplicate.rs:206:34
    |
 LL | trait TRS2: Iterator<Item: Copy, Item: Copy> {}
    |                      ----------  ^^^^^^^^^^ re-bound here
@@ -438,7 +498,7 @@ LL | trait TRS2: Iterator<Item: Copy, Item: Copy> {}
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:200:34
+  --> $DIR/duplicate.rs:206:34
    |
 LL | trait TRS2: Iterator<Item: Copy, Item: Copy> {}
    |                      ----------  ^^^^^^^^^^ re-bound here
@@ -448,7 +508,7 @@ LL | trait TRS2: Iterator<Item: Copy, Item: Copy> {}
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:204:37
+  --> $DIR/duplicate.rs:210:37
    |
 LL | trait TRS3: Iterator<Item: 'static, Item: 'static> {}
    |                      -------------  ^^^^^^^^^^^^^ re-bound here
@@ -456,7 +516,7 @@ LL | trait TRS3: Iterator<Item: 'static, Item: 'static> {}
    |                      `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:204:37
+  --> $DIR/duplicate.rs:210:37
    |
 LL | trait TRS3: Iterator<Item: 'static, Item: 'static> {}
    |                      -------------  ^^^^^^^^^^^^^ re-bound here
@@ -466,7 +526,7 @@ LL | trait TRS3: Iterator<Item: 'static, Item: 'static> {}
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:204:37
+  --> $DIR/duplicate.rs:210:37
    |
 LL | trait TRS3: Iterator<Item: 'static, Item: 'static> {}
    |                      -------------  ^^^^^^^^^^^^^ re-bound here
@@ -476,7 +536,7 @@ LL | trait TRS3: Iterator<Item: 'static, Item: 'static> {}
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:210:29
+  --> $DIR/duplicate.rs:216:29
    |
 LL |     T: Iterator<Item: Copy, Item: Send>,
    |                 ----------  ^^^^^^^^^^ re-bound here
@@ -484,7 +544,7 @@ LL |     T: Iterator<Item: Copy, Item: Send>,
    |                 `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:216:29
+  --> $DIR/duplicate.rs:222:29
    |
 LL |     T: Iterator<Item: Copy, Item: Copy>,
    |                 ----------  ^^^^^^^^^^ re-bound here
@@ -492,7 +552,7 @@ LL |     T: Iterator<Item: Copy, Item: Copy>,
    |                 `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:222:32
+  --> $DIR/duplicate.rs:228:32
    |
 LL |     T: Iterator<Item: 'static, Item: 'static>,
    |                 -------------  ^^^^^^^^^^^^^ re-bound here
@@ -500,7 +560,7 @@ LL |     T: Iterator<Item: 'static, Item: 'static>,
    |                 `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:228:32
+  --> $DIR/duplicate.rs:234:32
    |
 LL |     Self: Iterator<Item: Copy, Item: Send>,
    |                    ----------  ^^^^^^^^^^ re-bound here
@@ -508,7 +568,7 @@ LL |     Self: Iterator<Item: Copy, Item: Send>,
    |                    `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:228:32
+  --> $DIR/duplicate.rs:234:32
    |
 LL |     Self: Iterator<Item: Copy, Item: Send>,
    |                    ----------  ^^^^^^^^^^ re-bound here
@@ -518,7 +578,7 @@ LL |     Self: Iterator<Item: Copy, Item: Send>,
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:228:32
+  --> $DIR/duplicate.rs:234:32
    |
 LL |     Self: Iterator<Item: Copy, Item: Send>,
    |                    ----------  ^^^^^^^^^^ re-bound here
@@ -528,7 +588,7 @@ LL |     Self: Iterator<Item: Copy, Item: Send>,
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:236:32
+  --> $DIR/duplicate.rs:242:32
    |
 LL |     Self: Iterator<Item: Copy, Item: Copy>,
    |                    ----------  ^^^^^^^^^^ re-bound here
@@ -536,7 +596,7 @@ LL |     Self: Iterator<Item: Copy, Item: Copy>,
    |                    `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:236:32
+  --> $DIR/duplicate.rs:242:32
    |
 LL |     Self: Iterator<Item: Copy, Item: Copy>,
    |                    ----------  ^^^^^^^^^^ re-bound here
@@ -546,7 +606,7 @@ LL |     Self: Iterator<Item: Copy, Item: Copy>,
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:236:32
+  --> $DIR/duplicate.rs:242:32
    |
 LL |     Self: Iterator<Item: Copy, Item: Copy>,
    |                    ----------  ^^^^^^^^^^ re-bound here
@@ -556,7 +616,7 @@ LL |     Self: Iterator<Item: Copy, Item: Copy>,
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:244:35
+  --> $DIR/duplicate.rs:250:35
    |
 LL |     Self: Iterator<Item: 'static, Item: 'static>,
    |                    -------------  ^^^^^^^^^^^^^ re-bound here
@@ -564,7 +624,7 @@ LL |     Self: Iterator<Item: 'static, Item: 'static>,
    |                    `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:244:35
+  --> $DIR/duplicate.rs:250:35
    |
 LL |     Self: Iterator<Item: 'static, Item: 'static>,
    |                    -------------  ^^^^^^^^^^^^^ re-bound here
@@ -574,7 +634,7 @@ LL |     Self: Iterator<Item: 'static, Item: 'static>,
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:244:35
+  --> $DIR/duplicate.rs:250:35
    |
 LL |     Self: Iterator<Item: 'static, Item: 'static>,
    |                    -------------  ^^^^^^^^^^^^^ re-bound here
@@ -584,30 +644,60 @@ LL |     Self: Iterator<Item: 'static, Item: 'static>,
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:251:34
+  --> $DIR/duplicate.rs:257:34
+   |
+LL |     type A: Iterator<Item: Copy, Item: Send>;
+   |                      ----------  ^^^^^^^^^^ re-bound here
+   |                      |
+   |                      `Item` bound here first
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:257:34
    |
 LL |     type A: Iterator<Item: Copy, Item: Send>;
    |                      ----------  ^^^^^^^^^^ re-bound here
    |                      |
    |                      `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:262:34
+   |
+LL |     type A: Iterator<Item: Copy, Item: Copy>;
+   |                      ----------  ^^^^^^^^^^ re-bound here
+   |                      |
+   |                      `Item` bound here first
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:255:34
+  --> $DIR/duplicate.rs:262:34
    |
 LL |     type A: Iterator<Item: Copy, Item: Copy>;
    |                      ----------  ^^^^^^^^^^ re-bound here
    |                      |
    |                      `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
-  --> $DIR/duplicate.rs:259:37
+  --> $DIR/duplicate.rs:267:37
    |
 LL |     type A: Iterator<Item: 'static, Item: 'static>;
    |                      -------------  ^^^^^^^^^^^^^ re-bound here
    |                      |
    |                      `Item` bound here first
 
-error: aborting due to 72 previous errors
+error[E0719]: the value of the associated type `Item` in trait `Iterator` is already specified
+  --> $DIR/duplicate.rs:267:37
+   |
+LL |     type A: Iterator<Item: 'static, Item: 'static>;
+   |                      -------------  ^^^^^^^^^^^^^ re-bound here
+   |                      |
+   |                      `Item` bound here first
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 81 previous errors
 
 Some errors have detailed explanations: E0282, E0719.
 For more information about an error, try `rustc --explain E0282`.
diff --git a/tests/ui/associated-type-bounds/issue-102335-ty.rs b/tests/ui/associated-type-bounds/issue-102335-ty.rs
index 363df73c1ff..5fd8b71e679 100644
--- a/tests/ui/associated-type-bounds/issue-102335-ty.rs
+++ b/tests/ui/associated-type-bounds/issue-102335-ty.rs
@@ -1,6 +1,7 @@
 trait T {
     type A: S<C<i32 = u32> = ()>;
     //~^ ERROR associated type bindings are not allowed here
+    //~| ERROR associated type bindings are not allowed here
 }
 
 trait Q {}
diff --git a/tests/ui/associated-type-bounds/issue-102335-ty.stderr b/tests/ui/associated-type-bounds/issue-102335-ty.stderr
index 561ca15ab0d..3bd7566ad1e 100644
--- a/tests/ui/associated-type-bounds/issue-102335-ty.stderr
+++ b/tests/ui/associated-type-bounds/issue-102335-ty.stderr
@@ -4,6 +4,14 @@ error[E0229]: associated type bindings are not allowed here
 LL |     type A: S<C<i32 = u32> = ()>;
    |                 ^^^^^^^^^ associated type not allowed here
 
-error: aborting due to 1 previous error
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/issue-102335-ty.rs:2:17
+   |
+LL |     type A: S<C<i32 = u32> = ()>;
+   |                 ^^^^^^^^^ associated type not allowed here
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/ui/associated-type-bounds/issue-99828.rs b/tests/ui/associated-type-bounds/issue-99828.rs
index 67ba50f3cbc..ab3654131f1 100644
--- a/tests/ui/associated-type-bounds/issue-99828.rs
+++ b/tests/ui/associated-type-bounds/issue-99828.rs
@@ -1,5 +1,6 @@
 fn get_iter(vec: &[i32]) -> impl Iterator<Item = {}> + '_ {
     //~^ ERROR expected type, found constant
+    //~| ERROR expected type, found constant
     //~| ERROR associated const equality is incomplete
     vec.iter()
 }
diff --git a/tests/ui/associated-type-bounds/issue-99828.stderr b/tests/ui/associated-type-bounds/issue-99828.stderr
index 911f3ff0f5e..132d5251987 100644
--- a/tests/ui/associated-type-bounds/issue-99828.stderr
+++ b/tests/ui/associated-type-bounds/issue-99828.stderr
@@ -19,6 +19,18 @@ LL | fn get_iter(vec: &[i32]) -> impl Iterator<Item = {}> + '_ {
 note: the associated type is defined here
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
 
-error: aborting due to 2 previous errors
+error: expected type, found constant
+  --> $DIR/issue-99828.rs:1:50
+   |
+LL | fn get_iter(vec: &[i32]) -> impl Iterator<Item = {}> + '_ {
+   |                                           ----   ^^ unexpected constant
+   |                                           |
+   |                                           expected a type because of this associated type
+   |
+note: the associated type is defined here
+  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/async-await/in-trait/return-not-existing-pair.rs b/tests/ui/async-await/in-trait/return-not-existing-pair.rs
index 68be1358f81..3889efe1f2a 100644
--- a/tests/ui/async-await/in-trait/return-not-existing-pair.rs
+++ b/tests/ui/async-await/in-trait/return-not-existing-pair.rs
@@ -9,8 +9,7 @@ trait MyTrait<'a, 'b, T> {
 impl<'a, 'b, T, U> MyTrait<T> for U {
     //~^ ERROR: implicit elided lifetime not allowed here [E0726]
     async fn foo(_: T) -> (&'a U, &'b T) {}
-    //~^ ERROR: method `foo` has a `&self` declaration in the trait, but not in the impl [E0186]
-    //~| ERROR: mismatched types [E0308]
+    //~^ ERROR: mismatched types [E0308]
 }
 
 fn main() {}
diff --git a/tests/ui/async-await/in-trait/return-not-existing-pair.stderr b/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
index 4694e608097..13d3606abba 100644
--- a/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
+++ b/tests/ui/async-await/in-trait/return-not-existing-pair.stderr
@@ -15,15 +15,6 @@ error[E0412]: cannot find type `ConnImpl` in this scope
 LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
    |                                                ^^^^^^^^ not found in this scope
 
-error[E0186]: method `foo` has a `&self` declaration in the trait, but not in the impl
-  --> $DIR/return-not-existing-pair.rs:11:5
-   |
-LL |     async fn foo(&'a self, key: &'b T) -> (&'a ConnImpl, &'b T);
-   |     ------------------------------------------------------------ `&self` used in trait
-...
-LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `&self` in impl
-
 error[E0308]: mismatched types
   --> $DIR/return-not-existing-pair.rs:11:42
    |
@@ -33,7 +24,7 @@ LL |     async fn foo(_: T) -> (&'a U, &'b T) {}
    = note:  expected tuple `(&'a U, &'b T)`
            found unit type `()`
 
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0186, E0308, E0412, E0726.
-For more information about an error, try `rustc --explain E0186`.
+Some errors have detailed explanations: E0308, E0412, E0726.
+For more information about an error, try `rustc --explain E0308`.
diff --git a/tests/ui/async-await/in-trait/unconstrained-impl-region.rs b/tests/ui/async-await/in-trait/unconstrained-impl-region.rs
index 9382c232364..95ba1f3f277 100644
--- a/tests/ui/async-await/in-trait/unconstrained-impl-region.rs
+++ b/tests/ui/async-await/in-trait/unconstrained-impl-region.rs
@@ -14,6 +14,7 @@ impl<'a> Actor for () {
 //~^ ERROR the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates
     type Message = &'a ();
     async fn on_mount(self, _: impl Inbox<&'a ()>) {}
+    //~^ ERROR the trait bound `impl Inbox<&'a ()>: Inbox<&'a ()>` is not satisfied
 }
 
 fn main() {}
diff --git a/tests/ui/async-await/in-trait/unconstrained-impl-region.stderr b/tests/ui/async-await/in-trait/unconstrained-impl-region.stderr
index ef7e4ef0eb8..66819d1fcf7 100644
--- a/tests/ui/async-await/in-trait/unconstrained-impl-region.stderr
+++ b/tests/ui/async-await/in-trait/unconstrained-impl-region.stderr
@@ -1,9 +1,26 @@
+error[E0277]: the trait bound `impl Inbox<&'a ()>: Inbox<&'a ()>` is not satisfied
+  --> $DIR/unconstrained-impl-region.rs:16:5
+   |
+LL |     async fn on_mount(self, _: impl Inbox<&'a ()>) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Inbox<&'a ()>` is not implemented for `impl Inbox<&'a ()>`
+   |
+note: required by a bound in `<() as Actor>::on_mount`
+  --> $DIR/unconstrained-impl-region.rs:16:37
+   |
+LL |     async fn on_mount(self, _: impl Inbox<&'a ()>) {}
+   |                                     ^^^^^^^^^^^^^ required by this bound in `<() as Actor>::on_mount`
+help: consider further restricting this bound
+   |
+LL |     async fn on_mount(self, _: impl Inbox<&'a ()> + Inbox<&'a ()>) {}
+   |                                                   +++++++++++++++
+
 error[E0207]: the lifetime parameter `'a` is not constrained by the impl trait, self type, or predicates
   --> $DIR/unconstrained-impl-region.rs:13:6
    |
 LL | impl<'a> Actor for () {
    |      ^^ unconstrained lifetime parameter
 
-error: aborting due to 1 previous error
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0207`.
+Some errors have detailed explanations: E0207, E0277.
+For more information about an error, try `rustc --explain E0207`.
diff --git a/tests/ui/async-await/issues/issue-65159.rs b/tests/ui/async-await/issues/issue-65159.rs
index 781f8fe88d4..78492d55fda 100644
--- a/tests/ui/async-await/issues/issue-65159.rs
+++ b/tests/ui/async-await/issues/issue-65159.rs
@@ -4,6 +4,7 @@
 
 async fn copy() -> Result<()>
 //~^ ERROR enum takes 2 generic arguments
+//~| ERROR enum takes 2 generic arguments
 {
     Ok(())
 }
diff --git a/tests/ui/async-await/issues/issue-65159.stderr b/tests/ui/async-await/issues/issue-65159.stderr
index 19512116a66..834927060b1 100644
--- a/tests/ui/async-await/issues/issue-65159.stderr
+++ b/tests/ui/async-await/issues/issue-65159.stderr
@@ -11,6 +11,20 @@ help: add missing generic argument
 LL | async fn copy() -> Result<(), E>
    |                             +++
 
-error: aborting due to 1 previous error
+error[E0107]: enum takes 2 generic arguments but 1 generic argument was supplied
+  --> $DIR/issue-65159.rs:5:20
+   |
+LL | async fn copy() -> Result<()>
+   |                    ^^^^^^ -- supplied 1 generic argument
+   |                    |
+   |                    expected 2 generic arguments
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add missing generic argument
+   |
+LL | async fn copy() -> Result<(), E>
+   |                             +++
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0107`.
diff --git a/tests/ui/async-await/send-bound-async-closure.rs b/tests/ui/async-await/send-bound-async-closure.rs
index 2732fa5d466..e4a9ae4cc75 100644
--- a/tests/ui/async-await/send-bound-async-closure.rs
+++ b/tests/ui/async-await/send-bound-async-closure.rs
@@ -1,5 +1,8 @@
 //@ edition: 2021
 //@ check-pass
+//@ revisions: current next
+//@ ignore-compare-mode-next-solver (explicit revisions)
+//@[next] compile-flags: -Znext-solver
 
 // This test verifies that we do not create a query cycle when typechecking has several inference
 // variables that point to the same coroutine interior type.
diff --git a/tests/ui/borrowck/ice-mutability-error-slicing-121807.rs b/tests/ui/borrowck/ice-mutability-error-slicing-121807.rs
new file mode 100644
index 00000000000..bbdd895d763
--- /dev/null
+++ b/tests/ui/borrowck/ice-mutability-error-slicing-121807.rs
@@ -0,0 +1,27 @@
+//@ edition:2015
+// test for ICE #121807 begin <= end (12 <= 11) when slicing 'Self::Assoc<'_>'
+// fixed by #122749
+
+trait MemoryUnit { // ERROR: not all trait items implemented, missing: `read_word`
+    extern "C" fn read_word(&mut self) -> u8;
+    extern "C" fn read_dword(Self::Assoc<'_>) -> u16;
+    //~^ WARN anonymous parameters are deprecated and will be removed in the next edition
+    //~^^ WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2018!
+    //~^^^ ERROR associated type `Assoc` not found for `Self`
+}
+
+struct ROM {}
+
+impl MemoryUnit for ROM {
+//~^ ERROR not all trait items implemented, missing: `read_word`
+    extern "C" fn read_dword(&'s self) -> u16 {
+    //~^ ERROR use of undeclared lifetime name `'s`
+    //~^^ ERROR method `read_dword` has a `&self` declaration in the impl, but not in the trait
+        let a16 = self.read_word() as u16;
+        let b16 = self.read_word() as u16;
+
+        (b16 << 8) | a16
+    }
+}
+
+pub fn main() {}
diff --git a/tests/ui/borrowck/ice-mutability-error-slicing-121807.stderr b/tests/ui/borrowck/ice-mutability-error-slicing-121807.stderr
new file mode 100644
index 00000000000..3a6b8008fce
--- /dev/null
+++ b/tests/ui/borrowck/ice-mutability-error-slicing-121807.stderr
@@ -0,0 +1,53 @@
+error[E0261]: use of undeclared lifetime name `'s`
+  --> $DIR/ice-mutability-error-slicing-121807.rs:17:31
+   |
+LL |     extern "C" fn read_dword(&'s self) -> u16 {
+   |                               ^^ undeclared lifetime
+   |
+help: consider introducing lifetime `'s` here
+   |
+LL |     extern "C" fn read_dword<'s>(&'s self) -> u16 {
+   |                             ++++
+help: consider introducing lifetime `'s` here
+   |
+LL | impl<'s> MemoryUnit for ROM {
+   |     ++++
+
+warning: anonymous parameters are deprecated and will be removed in the next edition
+  --> $DIR/ice-mutability-error-slicing-121807.rs:7:30
+   |
+LL |     extern "C" fn read_dword(Self::Assoc<'_>) -> u16;
+   |                              ^^^^^^^^^^^^^^^ help: try naming the parameter or explicitly ignoring it: `_: Self::Assoc<'_>`
+   |
+   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2018!
+   = note: for more information, see issue #41686 <https://github.com/rust-lang/rust/issues/41686>
+   = note: `#[warn(anonymous_parameters)]` on by default
+
+error[E0220]: associated type `Assoc` not found for `Self`
+  --> $DIR/ice-mutability-error-slicing-121807.rs:7:36
+   |
+LL |     extern "C" fn read_dword(Self::Assoc<'_>) -> u16;
+   |                                    ^^^^^ associated type `Assoc` not found
+
+error[E0185]: method `read_dword` has a `&self` declaration in the impl, but not in the trait
+  --> $DIR/ice-mutability-error-slicing-121807.rs:17:5
+   |
+LL |     extern "C" fn read_dword(Self::Assoc<'_>) -> u16;
+   |     ------------------------------------------------- trait method declared without `&self`
+...
+LL |     extern "C" fn read_dword(&'s self) -> u16 {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `&self` used in impl
+
+error[E0046]: not all trait items implemented, missing: `read_word`
+  --> $DIR/ice-mutability-error-slicing-121807.rs:15:1
+   |
+LL |     extern "C" fn read_word(&mut self) -> u8;
+   |     ----------------------------------------- `read_word` from trait
+...
+LL | impl MemoryUnit for ROM {
+   | ^^^^^^^^^^^^^^^^^^^^^^^ missing `read_word` in implementation
+
+error: aborting due to 4 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0046, E0185, E0220, E0261.
+For more information about an error, try `rustc --explain E0046`.
diff --git a/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.rs b/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.rs
index 15be5fb3fac..ebffa237f96 100644
--- a/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.rs
+++ b/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.rs
@@ -15,7 +15,9 @@ impl MarketMultiplier {
 
 async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_> {
     //~^ ERROR struct takes 0 lifetime arguments but 1 lifetime argument was supplied
-    //~^^ ERROR struct takes 1 generic argument but 0 generic arguments were supplied
+    //~| ERROR struct takes 1 generic argument but 0 generic arguments were supplied
+    //~| ERROR struct takes 0 lifetime arguments but 1 lifetime argument was supplied
+    //~| ERROR struct takes 1 generic argument but 0 generic arguments were supplied
     LockedMarket(coroutine.lock().unwrap().buy())
 }
 
diff --git a/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.stderr b/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.stderr
index 516c1d065e6..c0b6dcd1512 100644
--- a/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.stderr
+++ b/tests/ui/borrowck/issue-82126-mismatched-subst-and-hir.stderr
@@ -7,7 +7,7 @@ LL | async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_>
    |                                                           expected 0 lifetime arguments
    |
 note: struct defined here, with 0 lifetime parameters
-  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:22:8
+  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:24:8
    |
 LL | struct LockedMarket<T>(T);
    |        ^^^^^^^^^^^^
@@ -19,7 +19,7 @@ LL | async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_>
    |                                                           ^^^^^^^^^^^^ expected 1 generic argument
    |
 note: struct defined here, with 1 generic parameter: `T`
-  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:22:8
+  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:24:8
    |
 LL | struct LockedMarket<T>(T);
    |        ^^^^^^^^^^^^ -
@@ -28,6 +28,38 @@ help: add missing generic argument
 LL | async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_, T> {
    |                                                                          +++
 
-error: aborting due to 2 previous errors
+error[E0107]: struct takes 0 lifetime arguments but 1 lifetime argument was supplied
+  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:16:59
+   |
+LL | async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_> {
+   |                                                           ^^^^^^^^^^^^---- help: remove these generics
+   |                                                           |
+   |                                                           expected 0 lifetime arguments
+   |
+note: struct defined here, with 0 lifetime parameters
+  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:24:8
+   |
+LL | struct LockedMarket<T>(T);
+   |        ^^^^^^^^^^^^
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0107]: struct takes 1 generic argument but 0 generic arguments were supplied
+  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:16:59
+   |
+LL | async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_> {
+   |                                                           ^^^^^^^^^^^^ expected 1 generic argument
+   |
+note: struct defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-82126-mismatched-subst-and-hir.rs:24:8
+   |
+LL | struct LockedMarket<T>(T);
+   |        ^^^^^^^^^^^^ -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add missing generic argument
+   |
+LL | async fn buy_lock(coroutine: &Mutex<MarketMultiplier>) -> LockedMarket<'_, T> {
+   |                                                                          +++
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0107`.
diff --git a/tests/ui/cfg/cfg-false-feature.stderr b/tests/ui/cfg/cfg-false-feature.stderr
index 9309b59ca59..542aeaf5caf 100644
--- a/tests/ui/cfg/cfg-false-feature.stderr
+++ b/tests/ui/cfg/cfg-false-feature.stderr
@@ -1,15 +1,3 @@
-warning: trait aliases are experimental
-  --> $DIR/cfg-false-feature.rs:12:1
-   |
-LL | trait A = Clone;
-   | ^^^^^^^^^^^^^^^^
-   |
-   = note: see issue #41517 <https://github.com/rust-lang/rust/issues/41517> for more information
-   = help: add `#![feature(trait_alias)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-   = warning: unstable syntax can change at any point in the future, causing a hard error!
-   = note: for more information, see issue #65860 <https://github.com/rust-lang/rust/issues/65860>
-
 warning: box pattern syntax is experimental
   --> $DIR/cfg-false-feature.rs:16:9
    |
@@ -22,5 +10,17 @@ LL |     let box _ = Box::new(0);
    = warning: unstable syntax can change at any point in the future, causing a hard error!
    = note: for more information, see issue #65860 <https://github.com/rust-lang/rust/issues/65860>
 
+warning: trait aliases are experimental
+  --> $DIR/cfg-false-feature.rs:12:1
+   |
+LL | trait A = Clone;
+   | ^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #41517 <https://github.com/rust-lang/rust/issues/41517> for more information
+   = help: add `#![feature(trait_alias)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = warning: unstable syntax can change at any point in the future, causing a hard error!
+   = note: for more information, see issue #65860 <https://github.com/rust-lang/rust/issues/65860>
+
 warning: 2 warnings emitted
 
diff --git a/tests/ui/const-generics/generic_const_exprs/issue-109141.rs b/tests/ui/const-generics/generic_const_exprs/issue-109141.rs
index 148c3bda8d2..c6dd981cced 100644
--- a/tests/ui/const-generics/generic_const_exprs/issue-109141.rs
+++ b/tests/ui/const-generics/generic_const_exprs/issue-109141.rs
@@ -4,6 +4,7 @@
 impl EntriesBuffer {
     fn a(&self) -> impl Iterator {
         self.0.iter_mut() //~ ERROR: cannot borrow `*self.0` as mutable, as it is behind a `&` reference
+                          //~| ERROR captures lifetime that does not appear in bounds
     }
 }
 
diff --git a/tests/ui/const-generics/generic_const_exprs/issue-109141.stderr b/tests/ui/const-generics/generic_const_exprs/issue-109141.stderr
index 8b8489ac2bc..7a9572d000d 100644
--- a/tests/ui/const-generics/generic_const_exprs/issue-109141.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/issue-109141.stderr
@@ -1,5 +1,5 @@
 error[E0425]: cannot find value `HashesEntryLEN` in this scope
-  --> $DIR/issue-109141.rs:10:32
+  --> $DIR/issue-109141.rs:11:32
    |
 LL | struct EntriesBuffer(Box<[[u8; HashesEntryLEN]; 5]>);
    |                                ^^^^^^^^^^^^^^ not found in this scope
@@ -20,7 +20,22 @@ help: consider changing this to be a mutable reference
 LL |     fn a(&mut self) -> impl Iterator {
    |          ~~~~~~~~~
 
-error: aborting due to 2 previous errors
+error[E0700]: hidden type for `impl Iterator` captures lifetime that does not appear in bounds
+  --> $DIR/issue-109141.rs:6:9
+   |
+LL |     fn a(&self) -> impl Iterator {
+   |          -----     ------------- opaque type defined here
+   |          |
+   |          hidden type `std::slice::IterMut<'_, [u8; {const error}]>` captures the anonymous lifetime defined here
+LL |         self.0.iter_mut()
+   |         ^^^^^^^^^^^^^^^^^
+   |
+help: to declare that `impl Iterator` captures `'_`, you can add an explicit `'_` lifetime bound
+   |
+LL |     fn a(&self) -> impl Iterator + '_ {
+   |                                  ++++
+
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0425, E0596.
+Some errors have detailed explanations: E0425, E0596, E0700.
 For more information about an error, try `rustc --explain E0425`.
diff --git a/tests/ui/const-generics/ice-unexpected-inference-var-122549.rs b/tests/ui/const-generics/ice-unexpected-inference-var-122549.rs
new file mode 100644
index 00000000000..126ea667290
--- /dev/null
+++ b/tests/ui/const-generics/ice-unexpected-inference-var-122549.rs
@@ -0,0 +1,29 @@
+// Regression test for https://github.com/rust-lang/rust/issues/122549
+// was fixed by https://github.com/rust-lang/rust/pull/122749
+
+trait ConstChunksExactTrait<T> {
+    fn const_chunks_exact<const N: usize>(&self) -> ConstChunksExact<'a, T, { N }>;
+    //~^ ERROR undeclared lifetime
+}
+
+impl<T> ConstChunksExactTrait<T> for [T] {}
+//~^ ERROR not all trait items implemented, missing: `const_chunks_exact`
+struct ConstChunksExact<'rem, T: 'a, const N: usize> {}
+//~^ ERROR use of undeclared lifetime name `'a`
+//~^^ ERROR lifetime parameter
+//~^^^ ERROR type parameter
+impl<'a, T, const N: usize> Iterator for ConstChunksExact<'a, T, {}> {
+//~^ ERROR the const parameter `N` is not constrained by the impl trait, self type, or predicates
+//~^^ ERROR mismatched types
+    type Item = &'a [T; N];
+}
+
+fn main() {
+    let slice = &[1i32, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+
+    let mut iter = [[1, 2, 3], [4, 5, 6], [7, 8, 9]].iter();
+
+    for a in slice.const_chunks_exact::<3>() {
+        assert_eq!(a, iter.next().unwrap());
+    }
+}
diff --git a/tests/ui/const-generics/ice-unexpected-inference-var-122549.stderr b/tests/ui/const-generics/ice-unexpected-inference-var-122549.stderr
new file mode 100644
index 00000000000..afad3388145
--- /dev/null
+++ b/tests/ui/const-generics/ice-unexpected-inference-var-122549.stderr
@@ -0,0 +1,67 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/ice-unexpected-inference-var-122549.rs:5:70
+   |
+LL |     fn const_chunks_exact<const N: usize>(&self) -> ConstChunksExact<'a, T, { N }>;
+   |                                                                      ^^ undeclared lifetime
+   |
+help: consider introducing lifetime `'a` here
+   |
+LL |     fn const_chunks_exact<'a, const N: usize>(&self) -> ConstChunksExact<'a, T, { N }>;
+   |                           +++
+help: consider introducing lifetime `'a` here
+   |
+LL | trait ConstChunksExactTrait<'a, T> {
+   |                             +++
+
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/ice-unexpected-inference-var-122549.rs:11:34
+   |
+LL | struct ConstChunksExact<'rem, T: 'a, const N: usize> {}
+   |                         -        ^^ undeclared lifetime
+   |                         |
+   |                         help: consider introducing lifetime `'a` here: `'a,`
+
+error[E0046]: not all trait items implemented, missing: `const_chunks_exact`
+  --> $DIR/ice-unexpected-inference-var-122549.rs:9:1
+   |
+LL |     fn const_chunks_exact<const N: usize>(&self) -> ConstChunksExact<'a, T, { N }>;
+   |     ------------------------------------------------------------------------------- `const_chunks_exact` from trait
+...
+LL | impl<T> ConstChunksExactTrait<T> for [T] {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ missing `const_chunks_exact` in implementation
+
+error[E0392]: lifetime parameter `'rem` is never used
+  --> $DIR/ice-unexpected-inference-var-122549.rs:11:25
+   |
+LL | struct ConstChunksExact<'rem, T: 'a, const N: usize> {}
+   |                         ^^^^ unused lifetime parameter
+   |
+   = help: consider removing `'rem`, referring to it in a field, or using a marker such as `PhantomData`
+
+error[E0392]: type parameter `T` is never used
+  --> $DIR/ice-unexpected-inference-var-122549.rs:11:31
+   |
+LL | struct ConstChunksExact<'rem, T: 'a, const N: usize> {}
+   |                               ^ unused type parameter
+   |
+   = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
+
+error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
+  --> $DIR/ice-unexpected-inference-var-122549.rs:15:13
+   |
+LL | impl<'a, T, const N: usize> Iterator for ConstChunksExact<'a, T, {}> {
+   |             ^^^^^^^^^^^^^^ unconstrained const parameter
+   |
+   = note: expressions using a const parameter must map each value to a distinct output value
+   = note: proving the result of expressions other than the parameter are unique is not supported
+
+error[E0308]: mismatched types
+  --> $DIR/ice-unexpected-inference-var-122549.rs:15:66
+   |
+LL | impl<'a, T, const N: usize> Iterator for ConstChunksExact<'a, T, {}> {
+   |                                                                  ^^ expected `usize`, found `()`
+
+error: aborting due to 7 previous errors
+
+Some errors have detailed explanations: E0046, E0207, E0261, E0308, E0392.
+For more information about an error, try `rustc --explain E0046`.
diff --git a/tests/ui/const-generics/late-bound-vars/late-bound-in-return-issue-77357.stderr b/tests/ui/const-generics/late-bound-vars/late-bound-in-return-issue-77357.stderr
index e42bb6e8cc5..7bef98b1d5d 100644
--- a/tests/ui/const-generics/late-bound-vars/late-bound-in-return-issue-77357.stderr
+++ b/tests/ui/const-generics/late-bound-vars/late-bound-in-return-issue-77357.stderr
@@ -4,46 +4,5 @@ error: cannot capture late-bound lifetime in constant
 LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
    |        -- lifetime defined here                     ^^
 
-error: overly complex generic constant
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constants
-   |
-   = help: consider moving this anonymous constant into a `const` function
-   = note: this operation may be supported in the future
-
-error[E0391]: cycle detected when evaluating type-level constant
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: ...which requires const-evaluating + checking `bug::{constant#0}`...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires caching mir of `bug::{constant#0}` for CTFE...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires elaborating drops for `bug::{constant#0}`...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-note: ...which requires borrow-checking `bug::{constant#0}`...
-  --> $DIR/late-bound-in-return-issue-77357.rs:9:46
-   |
-LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: ...which requires normalizing `Binder { value: ConstEvaluatable(UnevaluatedConst { def: DefId(0:8 ~ late_bound_in_return_issue_77357[9394]::bug::{constant#0}), args: [T/#0] }: usize), bound_vars: [] }`...
-   = note: ...which again requires evaluating type-level constant, completing the cycle
-   = note: cycle used when normalizing `&dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]>`
-   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
-
-error: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0391`.
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail.rs b/tests/ui/const-generics/min_const_generics/macro-fail.rs
index f3df96d468c..2f101ecfb1f 100644
--- a/tests/ui/const-generics/min_const_generics/macro-fail.rs
+++ b/tests/ui/const-generics/min_const_generics/macro-fail.rs
@@ -13,6 +13,7 @@ impl<const N: usize> Marker<N> for Example<N> {}
 
 fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
   //~^ ERROR: type provided when a constant was expected
+  //~| ERROR: type provided when a constant was expected
   Example::<gimme_a_const!(marker)>
   //~^ ERROR: type provided when a constant was expected
 }
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail.stderr b/tests/ui/const-generics/min_const_generics/macro-fail.stderr
index 06a111008a3..34764982bb0 100644
--- a/tests/ui/const-generics/min_const_generics/macro-fail.stderr
+++ b/tests/ui/const-generics/min_const_generics/macro-fail.stderr
@@ -1,5 +1,5 @@
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:29:27
+  --> $DIR/macro-fail.rs:30:27
    |
 LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
    |                                 ----------------------
@@ -13,7 +13,7 @@ LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:29:27
+  --> $DIR/macro-fail.rs:30:27
    |
 LL |   Example::<gimme_a_const!(marker)>
    |             ----------------------
@@ -41,7 +41,7 @@ LL |   let _fail = Example::<external_macro!()>;
    = note: this error originates in the macro `external_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: unexpected end of macro invocation
-  --> $DIR/macro-fail.rs:39:25
+  --> $DIR/macro-fail.rs:40:25
    |
 LL |     macro_rules! gimme_a_const {
    |     -------------------------- when calling this macro
@@ -50,7 +50,7 @@ LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^ missing tokens in macro arguments
    |
 note: while trying to match meta-variable `$rusty:ident`
-  --> $DIR/macro-fail.rs:29:8
+  --> $DIR/macro-fail.rs:30:8
    |
 LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    |        ^^^^^^^^^^^^^
@@ -62,23 +62,31 @@ LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
    |                                 ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:16:13
+  --> $DIR/macro-fail.rs:14:33
+   |
+LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0747]: type provided when a constant was expected
+  --> $DIR/macro-fail.rs:17:13
    |
 LL |   Example::<gimme_a_const!(marker)>
    |             ^^^^^^^^^^^^^^^^^^^^^^
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:36:25
+  --> $DIR/macro-fail.rs:37:25
    |
 LL |   let _fail = Example::<external_macro!()>;
    |                         ^^^^^^^^^^^^^^^^^
 
 error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:39:25
+  --> $DIR/macro-fail.rs:40:25
    |
 LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^
 
-error: aborting due to 8 previous errors
+error: aborting due to 9 previous errors
 
 For more information about this error, try `rustc --explain E0747`.
diff --git a/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr b/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr
index 14a4cb0217f..c3b641a899a 100644
--- a/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-called-fn.noopt.stderr
@@ -1,19 +1,19 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-called-fn.rs:9:19
+  --> $DIR/collect-in-called-fn.rs:10:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-called-fn.rs:9:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-called-fn.rs:10:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/collect-in-called-fn.rs:18:17
+  --> $DIR/collect-in-called-fn.rs:19:17
    |
 LL |         let _ = Fail::<T>::C;
    |                 ^^^^^^^^^^^^
 
 note: the above error was encountered while instantiating `fn called::<i32>`
-  --> $DIR/collect-in-called-fn.rs:23:5
+  --> $DIR/collect-in-called-fn.rs:24:5
    |
 LL |     called::<i32>();
    |     ^^^^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr b/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr
index 14a4cb0217f..c3b641a899a 100644
--- a/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-called-fn.opt.stderr
@@ -1,19 +1,19 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-called-fn.rs:9:19
+  --> $DIR/collect-in-called-fn.rs:10:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-called-fn.rs:9:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-called-fn.rs:10:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/collect-in-called-fn.rs:18:17
+  --> $DIR/collect-in-called-fn.rs:19:17
    |
 LL |         let _ = Fail::<T>::C;
    |                 ^^^^^^^^^^^^
 
 note: the above error was encountered while instantiating `fn called::<i32>`
-  --> $DIR/collect-in-called-fn.rs:23:5
+  --> $DIR/collect-in-called-fn.rs:24:5
    |
 LL |     called::<i32>();
    |     ^^^^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/collect-in-called-fn.rs b/tests/ui/consts/required-consts/collect-in-called-fn.rs
index 55133a10cd9..93947950af2 100644
--- a/tests/ui/consts/required-consts/collect-in-called-fn.rs
+++ b/tests/ui/consts/required-consts/collect-in-called-fn.rs
@@ -1,5 +1,6 @@
 //@revisions: noopt opt
 //@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
 //! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
 //! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)
diff --git a/tests/ui/consts/required-consts/collect-in-dead-closure.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-closure.noopt.stderr
new file mode 100644
index 00000000000..75c3575a110
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-closure.noopt.stderr
@@ -0,0 +1,23 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-closure.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-closure.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-closure.rs:17:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $DIR/collect-in-dead-closure.rs:24:33
+   |
+LL |         let _closure: fn() = || not_called::<T>();
+   |                                 ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-closure.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-closure.opt.stderr
new file mode 100644
index 00000000000..75c3575a110
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-closure.opt.stderr
@@ -0,0 +1,23 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-closure.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-closure.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-closure.rs:17:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $DIR/collect-in-dead-closure.rs:24:33
+   |
+LL |         let _closure: fn() = || not_called::<T>();
+   |                                 ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-closure.rs b/tests/ui/consts/required-consts/collect-in-dead-closure.rs
new file mode 100644
index 00000000000..a00214c62db
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-closure.rs
@@ -0,0 +1,30 @@
+//@revisions: noopt opt
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
+//@[opt] compile-flags: -O
+//! This fails without optimizations, so it should also fail with optimizations.
+
+struct Fail<T>(T);
+impl<T> Fail<T> {
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
+}
+
+// This function is not actually called, but it is mentioned in a closure that is coerced to a
+// function pointer in dead code in a function that is called. Make sure we still find this error.
+#[inline(never)]
+fn not_called<T>() {
+    if false {
+        let _ = Fail::<T>::C;
+    }
+}
+
+#[inline(never)]
+fn called<T>() {
+    if false {
+        let _closure: fn() = || not_called::<T>();
+    }
+}
+
+pub fn main() {
+    called::<i32>();
+}
diff --git a/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr
index 0bf231d09f1..73790f7517d 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-drop.noopt.stderr
@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-dead-drop.rs:12:19
+  --> $DIR/collect-in-dead-drop.rs:9:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-drop.rs:12:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-drop.rs:9:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/collect-in-dead-drop.rs:19:17
+  --> $DIR/collect-in-dead-drop.rs:16:17
    |
 LL |         let _ = Fail::<T>::C;
    |                 ^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/collect-in-dead-drop.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-drop.opt.stderr
new file mode 100644
index 00000000000..73790f7517d
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-drop.opt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-drop.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-drop.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-drop.rs:16:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn <Fail<i32> as std::ops::Drop>::drop`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-drop.rs b/tests/ui/consts/required-consts/collect-in-dead-drop.rs
index c9ffcec6903..389fcf5dfc9 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-drop.rs
+++ b/tests/ui/consts/required-consts/collect-in-dead-drop.rs
@@ -1,15 +1,12 @@
 //@revisions: noopt opt
-//@[noopt] build-fail
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
-//FIXME: `opt` revision currently does not stop with an error due to
-//<https://github.com/rust-lang/rust/issues/107503>.
-//@[opt] build-pass
-//! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
-//! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)
+//! This fails without optimizations, so it should also fail with optimizations.
 
 struct Fail<T>(T);
 impl<T> Fail<T> {
-    const C: () = panic!(); //[noopt]~ERROR evaluation of `Fail::<i32>::C` failed
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
 }
 
 // This function is not actually called, but is mentioned implicitly as destructor in dead code in a
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.noopt.stderr
new file mode 100644
index 00000000000..706c0d55b62
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.noopt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn-behind-assoc-type.rs:10:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn-behind-assoc-type.rs:10:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn-behind-assoc-type.rs:16:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.opt.stderr
new file mode 100644
index 00000000000..706c0d55b62
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.opt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn-behind-assoc-type.rs:10:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn-behind-assoc-type.rs:10:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn-behind-assoc-type.rs:16:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.rs b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.rs
new file mode 100644
index 00000000000..9c36af50bb7
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-assoc-type.rs
@@ -0,0 +1,49 @@
+#![feature(impl_trait_in_assoc_type)]
+//@revisions: noopt opt
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
+//@[opt] compile-flags: -O
+//! This fails without optimizations, so it should also fail with optimizations.
+
+struct Fail<T>(T);
+impl<T> Fail<T> {
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
+}
+
+#[inline(never)]
+fn not_called<T>() {
+    if false {
+        let _ = Fail::<T>::C;
+    }
+}
+
+#[inline(never)]
+fn callit_not(f: impl Fn()) {
+    if false {
+        f();
+    }
+}
+
+// Using `Fn` here is important; with `FnOnce` another shim gets involved which somehow makes this
+// easier to collect properly.
+trait Hideaway {
+    type T: Fn();
+    const C: Self::T;
+}
+impl Hideaway for () {
+    type T = impl Fn();
+    const C: Self::T = not_called::<i32>;
+}
+
+#[inline(never)]
+fn reveal<T: Hideaway>() {
+    if false {
+        callit_not(T::C);
+    }
+}
+
+fn main() {
+    if false {
+        reveal::<()>()
+    }
+}
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.noopt.stderr
new file mode 100644
index 00000000000..581edd2b7b8
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.noopt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn-behind-generic.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn-behind-generic.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn-behind-generic.rs:15:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.opt.stderr
new file mode 100644
index 00000000000..581edd2b7b8
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.opt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn-behind-generic.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn-behind-generic.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn-behind-generic.rs:15:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.rs b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.rs
new file mode 100644
index 00000000000..5829d914ee1
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-generic.rs
@@ -0,0 +1,30 @@
+//@revisions: noopt opt
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
+//@[opt] compile-flags: -O
+//! This fails without optimizations, so it should also fail with optimizations.
+
+struct Fail<T>(T);
+impl<T> Fail<T> {
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
+}
+
+#[inline(never)]
+fn not_called<T>() {
+    if false {
+        let _ = Fail::<T>::C;
+    }
+}
+
+#[inline(never)]
+fn callit_not(f: impl Fn()) {
+    if false {
+        f();
+    }
+}
+
+fn main() {
+    if false {
+        callit_not(not_called::<i32>)
+    }
+}
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.noopt.stderr
new file mode 100644
index 00000000000..07e46b8a816
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.noopt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `m::Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn-behind-opaque-type.rs:11:23
+   |
+LL |         const C: () = panic!();
+   |                       ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn-behind-opaque-type.rs:11:23
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn-behind-opaque-type.rs:19:21
+   |
+LL |             let _ = Fail::<T>::C;
+   |                     ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn m::not_called::<i32>`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.opt.stderr
new file mode 100644
index 00000000000..07e46b8a816
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.opt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `m::Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn-behind-opaque-type.rs:11:23
+   |
+LL |         const C: () = panic!();
+   |                       ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn-behind-opaque-type.rs:11:23
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn-behind-opaque-type.rs:19:21
+   |
+LL |             let _ = Fail::<T>::C;
+   |                     ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn m::not_called::<i32>`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.rs b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.rs
new file mode 100644
index 00000000000..795e021ceb0
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn-behind-opaque-type.rs
@@ -0,0 +1,37 @@
+//@revisions: noopt opt
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
+//@[opt] compile-flags: -O
+//! This fails without optimizations, so it should also fail with optimizations.
+#![feature(type_alias_impl_trait)]
+
+mod m {
+    struct Fail<T>(T);
+    impl<T> Fail<T> {
+        const C: () = panic!(); //~ERROR evaluation of `m::Fail::<i32>::C` failed
+    }
+
+    pub type NotCalledFn = impl Fn();
+
+    #[inline(never)]
+    fn not_called<T>() {
+        if false {
+            let _ = Fail::<T>::C;
+        }
+    }
+
+    fn mk_not_called() -> NotCalledFn {
+        not_called::<i32>
+    }
+}
+
+fn main() {
+    // This does not involve a constant of `FnDef` type, it generates the value via unsafe
+    // shenanigans instead. This ensures that we check all `FnDef` types that occur in a function,
+    // not just those of constants. Furthermore the `FnDef` is behind an opaque type which bust be
+    // normalized away to reveal the function type.
+    if false {
+        let x: m::NotCalledFn = unsafe { std::mem::transmute(()) };
+        x();
+    }
+}
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr
index 8bb99efe8e4..52462076ff9 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn.noopt.stderr
@@ -1,19 +1,19 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-dead-fn.rs:12:19
+  --> $DIR/collect-in-dead-fn.rs:9:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn.rs:12:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn.rs:9:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/collect-in-dead-fn.rs:22:17
+  --> $DIR/collect-in-dead-fn.rs:19:17
    |
 LL |         let _ = Fail::<T>::C;
    |                 ^^^^^^^^^^^^
 
 note: the above error was encountered while instantiating `fn not_called::<i32>`
-  --> $DIR/collect-in-dead-fn.rs:29:9
+  --> $DIR/collect-in-dead-fn.rs:26:9
    |
 LL |         not_called::<T>();
    |         ^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fn.opt.stderr
new file mode 100644
index 00000000000..52462076ff9
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn.opt.stderr
@@ -0,0 +1,23 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fn.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fn.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fn.rs:19:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $DIR/collect-in-dead-fn.rs:26:9
+   |
+LL |         not_called::<T>();
+   |         ^^^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fn.rs b/tests/ui/consts/required-consts/collect-in-dead-fn.rs
index 9e6b1519153..1c95e0c303f 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-fn.rs
+++ b/tests/ui/consts/required-consts/collect-in-dead-fn.rs
@@ -1,15 +1,12 @@
 //@revisions: noopt opt
-//@[noopt] build-fail
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
-//FIXME: `opt` revision currently does not stop with an error due to
-//<https://github.com/rust-lang/rust/issues/107503>.
-//@[opt] build-pass
-//! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
-//! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)
+//! This fails without optimizations, so it should also fail with optimizations.
 
 struct Fail<T>(T);
 impl<T> Fail<T> {
-    const C: () = panic!(); //[noopt]~ERROR evaluation of `Fail::<i32>::C` failed
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
 }
 
 // This function is not actually called, but it is mentioned in dead code in a function that is
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.noopt.stderr
new file mode 100644
index 00000000000..dea2a342383
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.noopt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Late::<i32>::FAIL` failed
+  --> $DIR/collect-in-dead-fnptr-in-const.rs:9:22
+   |
+LL |     const FAIL: () = panic!();
+   |                      ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fnptr-in-const.rs:9:22
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fnptr-in-const.rs:10:28
+   |
+LL |     const FNPTR: fn() = || Self::FAIL;
+   |                            ^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn Late::<i32>::FNPTR::{closure#0}`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.opt.stderr
new file mode 100644
index 00000000000..dea2a342383
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.opt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Late::<i32>::FAIL` failed
+  --> $DIR/collect-in-dead-fnptr-in-const.rs:9:22
+   |
+LL |     const FAIL: () = panic!();
+   |                      ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fnptr-in-const.rs:9:22
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fnptr-in-const.rs:10:28
+   |
+LL |     const FNPTR: fn() = || Self::FAIL;
+   |                            ^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn Late::<i32>::FNPTR::{closure#0}`
+  --> $SRC_DIR/core/src/ops/function.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.rs b/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.rs
new file mode 100644
index 00000000000..8b6344c93f3
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fnptr-in-const.rs
@@ -0,0 +1,34 @@
+//@revisions: noopt opt
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
+//@[opt] compile-flags: -O
+//! This fails without optimizations, so it should also fail with optimizations.
+
+struct Late<T>(T);
+impl<T> Late<T> {
+    const FAIL: () = panic!(); //~ERROR evaluation of `Late::<i32>::FAIL` failed
+    const FNPTR: fn() = || Self::FAIL;
+}
+
+// This function is not actually called, but it is mentioned in dead code in a function that is
+// called. The function then mentions a const that evaluates to a fnptr that points to a function
+// that used a const that fails to evaluate.
+// This tests that when processing mentioned items, we also check the fnptrs in the final values
+// of consts that we encounter.
+#[inline(never)]
+fn not_called<T>() {
+    if false {
+        let _ = Late::<T>::FNPTR;
+    }
+}
+
+#[inline(never)]
+fn called<T>() {
+    if false {
+        not_called::<T>();
+    }
+}
+
+pub fn main() {
+    called::<i32>();
+}
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fnptr.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fnptr.noopt.stderr
new file mode 100644
index 00000000000..51c68782687
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fnptr.noopt.stderr
@@ -0,0 +1,23 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fnptr.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fnptr.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fnptr.rs:18:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $DIR/collect-in-dead-fnptr.rs:27:28
+   |
+LL |         let _fnptr: fn() = not_called::<T>;
+   |                            ^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fnptr.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-fnptr.opt.stderr
new file mode 100644
index 00000000000..51c68782687
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fnptr.opt.stderr
@@ -0,0 +1,23 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-fnptr.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-fnptr.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-fnptr.rs:18:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn not_called::<i32>`
+  --> $DIR/collect-in-dead-fnptr.rs:27:28
+   |
+LL |         let _fnptr: fn() = not_called::<T>;
+   |                            ^^^^^^^^^^^^^^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-fnptr.rs b/tests/ui/consts/required-consts/collect-in-dead-fnptr.rs
new file mode 100644
index 00000000000..acbe34829e8
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-fnptr.rs
@@ -0,0 +1,33 @@
+//@revisions: noopt opt
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
+//@[opt] compile-flags: -O
+//! This fails without optimizations, so it should also fail with optimizations.
+
+struct Fail<T>(T);
+impl<T> Fail<T> {
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
+}
+
+// This function is not actually called, but it is mentioned in dead code in a function that is
+// called. Make sure we still find this error.
+// This ensures that we consider ReifyFnPointer coercions when gathering "mentioned" items.
+#[inline(never)]
+fn not_called<T>() {
+    if false {
+        let _ = Fail::<T>::C;
+    }
+}
+
+#[inline(never)]
+fn called<T>() {
+    if false {
+        // We don't call the function, but turn it to a function pointer.
+        // Make sure it still gest added to `mentioned_items`.
+        let _fnptr: fn() = not_called::<T>;
+    }
+}
+
+pub fn main() {
+    called::<i32>();
+}
diff --git a/tests/ui/consts/required-consts/collect-in-dead-forget.rs b/tests/ui/consts/required-consts/collect-in-dead-forget.rs
index 720b7a499f7..7586004116c 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-forget.rs
+++ b/tests/ui/consts/required-consts/collect-in-dead-forget.rs
@@ -1,8 +1,8 @@
 //@revisions: noopt opt
 //@build-pass
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
-//! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
-//! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)
+//! This passes without optimizations, so it can (and should) also pass with optimizations.
 
 struct Fail<T>(T);
 impl<T> Fail<T> {
diff --git a/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr
index 5b1df78b232..2ab1f80e2d3 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-move.noopt.stderr
@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-dead-move.rs:12:19
+  --> $DIR/collect-in-dead-move.rs:9:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-move.rs:12:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-move.rs:9:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/collect-in-dead-move.rs:19:17
+  --> $DIR/collect-in-dead-move.rs:16:17
    |
 LL |         let _ = Fail::<T>::C;
    |                 ^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/collect-in-dead-move.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-move.opt.stderr
new file mode 100644
index 00000000000..2ab1f80e2d3
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-move.opt.stderr
@@ -0,0 +1,20 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-move.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-move.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-move.rs:16:17
+   |
+LL |         let _ = Fail::<T>::C;
+   |                 ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn <Fail<i32> as std::ops::Drop>::drop`
+  --> $SRC_DIR/core/src/ptr/mod.rs:LL:COL
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-move.rs b/tests/ui/consts/required-consts/collect-in-dead-move.rs
index f3a6ba8a657..6a224a375cf 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-move.rs
+++ b/tests/ui/consts/required-consts/collect-in-dead-move.rs
@@ -1,15 +1,12 @@
 //@revisions: noopt opt
-//@[noopt] build-fail
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
-//FIXME: `opt` revision currently does not stop with an error due to
-//<https://github.com/rust-lang/rust/issues/107503>.
-//@[opt] build-pass
-//! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
-//! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)
+//! This fails without optimizations, so it should also fail with optimizations.
 
 struct Fail<T>(T);
 impl<T> Fail<T> {
-    const C: () = panic!(); //[noopt]~ERROR evaluation of `Fail::<i32>::C` failed
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
 }
 
 // This function is not actually called, but is mentioned implicitly as destructor in dead code in a
diff --git a/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr b/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr
index 56b6989b441..b4e18706489 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr
+++ b/tests/ui/consts/required-consts/collect-in-dead-vtable.noopt.stderr
@@ -1,21 +1,21 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/collect-in-dead-vtable.rs:12:19
+  --> $DIR/collect-in-dead-vtable.rs:9:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-vtable.rs:12:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-vtable.rs:9:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/collect-in-dead-vtable.rs:26:21
+  --> $DIR/collect-in-dead-vtable.rs:22:21
    |
 LL |             let _ = Fail::<T>::C;
    |                     ^^^^^^^^^^^^
 
 note: the above error was encountered while instantiating `fn <std::vec::Vec<i32> as MyTrait>::not_called`
-  --> $DIR/collect-in-dead-vtable.rs:35:40
+  --> $DIR/collect-in-dead-vtable.rs:31:40
    |
-LL |         let gen_vtable: &dyn MyTrait = &v; // vtable "appears" here
+LL |         let gen_vtable: &dyn MyTrait = &v; // vtable is "mentioned" here
    |                                        ^^
 
 error: aborting due to 1 previous error
diff --git a/tests/ui/consts/required-consts/collect-in-dead-vtable.opt.stderr b/tests/ui/consts/required-consts/collect-in-dead-vtable.opt.stderr
new file mode 100644
index 00000000000..b4e18706489
--- /dev/null
+++ b/tests/ui/consts/required-consts/collect-in-dead-vtable.opt.stderr
@@ -0,0 +1,23 @@
+error[E0080]: evaluation of `Fail::<i32>::C` failed
+  --> $DIR/collect-in-dead-vtable.rs:9:19
+   |
+LL |     const C: () = panic!();
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/collect-in-dead-vtable.rs:9:19
+   |
+   = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+  --> $DIR/collect-in-dead-vtable.rs:22:21
+   |
+LL |             let _ = Fail::<T>::C;
+   |                     ^^^^^^^^^^^^
+
+note: the above error was encountered while instantiating `fn <std::vec::Vec<i32> as MyTrait>::not_called`
+  --> $DIR/collect-in-dead-vtable.rs:31:40
+   |
+LL |         let gen_vtable: &dyn MyTrait = &v; // vtable is "mentioned" here
+   |                                        ^^
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
diff --git a/tests/ui/consts/required-consts/collect-in-dead-vtable.rs b/tests/ui/consts/required-consts/collect-in-dead-vtable.rs
index f21a1cc1fc2..f63207eafec 100644
--- a/tests/ui/consts/required-consts/collect-in-dead-vtable.rs
+++ b/tests/ui/consts/required-consts/collect-in-dead-vtable.rs
@@ -1,15 +1,12 @@
 //@revisions: noopt opt
-//@[noopt] build-fail
+//@ build-fail
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
-//FIXME: `opt` revision currently does not stop with an error due to
-//<https://github.com/rust-lang/rust/issues/107503>.
-//@[opt] build-pass
-//! Make sure we detect erroneous constants post-monomorphization even when they are unused. This is
-//! crucial, people rely on it for soundness. (https://github.com/rust-lang/rust/issues/112090)
+//! This fails without optimizations, so it should also fail with optimizations.
 
 struct Fail<T>(T);
 impl<T> Fail<T> {
-    const C: () = panic!(); //[noopt]~ERROR evaluation of `Fail::<i32>::C` failed
+    const C: () = panic!(); //~ERROR evaluation of `Fail::<i32>::C` failed
 }
 
 trait MyTrait {
@@ -18,8 +15,7 @@ trait MyTrait {
 
 // This function is not actually called, but it is mentioned in a vtable in a function that is
 // called. Make sure we still find this error.
-// This relies on mono-item collection checking `required_consts` in functions that are referenced
-// in vtables that syntactically appear in collected functions (even inside dead code).
+// This ensures that we are properly considering vtables when gathering "mentioned" items.
 impl<T> MyTrait for Vec<T> {
     fn not_called(&self) {
         if false {
@@ -32,7 +28,7 @@ impl<T> MyTrait for Vec<T> {
 fn called<T>() {
     if false {
         let v: Vec<T> = Vec::new();
-        let gen_vtable: &dyn MyTrait = &v; // vtable "appears" here
+        let gen_vtable: &dyn MyTrait = &v; // vtable is "mentioned" here
     }
 }
 
diff --git a/tests/ui/consts/required-consts/interpret-in-const-called-fn.noopt.stderr b/tests/ui/consts/required-consts/interpret-in-const-called-fn.noopt.stderr
index 75304591b9f..0e3bbbcc2ec 100644
--- a/tests/ui/consts/required-consts/interpret-in-const-called-fn.noopt.stderr
+++ b/tests/ui/consts/required-consts/interpret-in-const-called-fn.noopt.stderr
@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/interpret-in-const-called-fn.rs:7:19
+  --> $DIR/interpret-in-const-called-fn.rs:8:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-const-called-fn.rs:7:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-const-called-fn.rs:8:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/interpret-in-const-called-fn.rs:16:9
+  --> $DIR/interpret-in-const-called-fn.rs:17:9
    |
 LL |         Fail::<T>::C;
    |         ^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/interpret-in-const-called-fn.opt.stderr b/tests/ui/consts/required-consts/interpret-in-const-called-fn.opt.stderr
index 75304591b9f..0e3bbbcc2ec 100644
--- a/tests/ui/consts/required-consts/interpret-in-const-called-fn.opt.stderr
+++ b/tests/ui/consts/required-consts/interpret-in-const-called-fn.opt.stderr
@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/interpret-in-const-called-fn.rs:7:19
+  --> $DIR/interpret-in-const-called-fn.rs:8:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-const-called-fn.rs:7:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-const-called-fn.rs:8:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/interpret-in-const-called-fn.rs:16:9
+  --> $DIR/interpret-in-const-called-fn.rs:17:9
    |
 LL |         Fail::<T>::C;
    |         ^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/interpret-in-const-called-fn.rs b/tests/ui/consts/required-consts/interpret-in-const-called-fn.rs
index c409fae0bb9..f2e83f56f37 100644
--- a/tests/ui/consts/required-consts/interpret-in-const-called-fn.rs
+++ b/tests/ui/consts/required-consts/interpret-in-const-called-fn.rs
@@ -1,4 +1,5 @@
 //@revisions: noopt opt
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
 //! Make sure we error on erroneous consts even if they are unused.
 
diff --git a/tests/ui/consts/required-consts/interpret-in-promoted.noopt.stderr b/tests/ui/consts/required-consts/interpret-in-promoted.noopt.stderr
index 491131daf8d..6ab991b6471 100644
--- a/tests/ui/consts/required-consts/interpret-in-promoted.noopt.stderr
+++ b/tests/ui/consts/required-consts/interpret-in-promoted.noopt.stderr
@@ -6,18 +6,18 @@ error[E0080]: evaluation of constant value failed
 note: inside `unreachable_unchecked`
   --> $SRC_DIR/core/src/hint.rs:LL:COL
 note: inside `ub`
-  --> $DIR/interpret-in-promoted.rs:6:5
+  --> $DIR/interpret-in-promoted.rs:7:5
    |
 LL |     std::hint::unreachable_unchecked();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: inside `FOO`
-  --> $DIR/interpret-in-promoted.rs:12:28
+  --> $DIR/interpret-in-promoted.rs:13:28
    |
 LL |     let _x: &'static () = &ub();
    |                            ^^^^
 
 note: erroneous constant encountered
-  --> $DIR/interpret-in-promoted.rs:12:27
+  --> $DIR/interpret-in-promoted.rs:13:27
    |
 LL |     let _x: &'static () = &ub();
    |                           ^^^^^
diff --git a/tests/ui/consts/required-consts/interpret-in-promoted.opt.stderr b/tests/ui/consts/required-consts/interpret-in-promoted.opt.stderr
index 491131daf8d..6ab991b6471 100644
--- a/tests/ui/consts/required-consts/interpret-in-promoted.opt.stderr
+++ b/tests/ui/consts/required-consts/interpret-in-promoted.opt.stderr
@@ -6,18 +6,18 @@ error[E0080]: evaluation of constant value failed
 note: inside `unreachable_unchecked`
   --> $SRC_DIR/core/src/hint.rs:LL:COL
 note: inside `ub`
-  --> $DIR/interpret-in-promoted.rs:6:5
+  --> $DIR/interpret-in-promoted.rs:7:5
    |
 LL |     std::hint::unreachable_unchecked();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 note: inside `FOO`
-  --> $DIR/interpret-in-promoted.rs:12:28
+  --> $DIR/interpret-in-promoted.rs:13:28
    |
 LL |     let _x: &'static () = &ub();
    |                            ^^^^
 
 note: erroneous constant encountered
-  --> $DIR/interpret-in-promoted.rs:12:27
+  --> $DIR/interpret-in-promoted.rs:13:27
    |
 LL |     let _x: &'static () = &ub();
    |                           ^^^^^
diff --git a/tests/ui/consts/required-consts/interpret-in-promoted.rs b/tests/ui/consts/required-consts/interpret-in-promoted.rs
index 9c2cf4e70d3..187494180ad 100644
--- a/tests/ui/consts/required-consts/interpret-in-promoted.rs
+++ b/tests/ui/consts/required-consts/interpret-in-promoted.rs
@@ -1,4 +1,5 @@
 //@revisions: noopt opt
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
 //! Make sure we error on erroneous consts even if they are unused.
 
diff --git a/tests/ui/consts/required-consts/interpret-in-static.noopt.stderr b/tests/ui/consts/required-consts/interpret-in-static.noopt.stderr
index 159c9449fc0..5e8da609e76 100644
--- a/tests/ui/consts/required-consts/interpret-in-static.noopt.stderr
+++ b/tests/ui/consts/required-consts/interpret-in-static.noopt.stderr
@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/interpret-in-static.rs:7:19
+  --> $DIR/interpret-in-static.rs:8:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-static.rs:7:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-static.rs:8:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/interpret-in-static.rs:15:9
+  --> $DIR/interpret-in-static.rs:16:9
    |
 LL |         Fail::<i32>::C;
    |         ^^^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/interpret-in-static.opt.stderr b/tests/ui/consts/required-consts/interpret-in-static.opt.stderr
index 159c9449fc0..5e8da609e76 100644
--- a/tests/ui/consts/required-consts/interpret-in-static.opt.stderr
+++ b/tests/ui/consts/required-consts/interpret-in-static.opt.stderr
@@ -1,13 +1,13 @@
 error[E0080]: evaluation of `Fail::<i32>::C` failed
-  --> $DIR/interpret-in-static.rs:7:19
+  --> $DIR/interpret-in-static.rs:8:19
    |
 LL |     const C: () = panic!();
-   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-static.rs:7:19
+   |                   ^^^^^^^^ the evaluated program panicked at 'explicit panic', $DIR/interpret-in-static.rs:8:19
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/interpret-in-static.rs:15:9
+  --> $DIR/interpret-in-static.rs:16:9
    |
 LL |         Fail::<i32>::C;
    |         ^^^^^^^^^^^^^^
diff --git a/tests/ui/consts/required-consts/interpret-in-static.rs b/tests/ui/consts/required-consts/interpret-in-static.rs
index 559e281b2b0..8bacd030440 100644
--- a/tests/ui/consts/required-consts/interpret-in-static.rs
+++ b/tests/ui/consts/required-consts/interpret-in-static.rs
@@ -1,4 +1,5 @@
 //@revisions: noopt opt
+//@[noopt] compile-flags: -Copt-level=0
 //@[opt] compile-flags: -O
 //! Make sure we error on erroneous consts even if they are unused.
 
diff --git a/tests/ui/coroutine/gen_block_is_fused_iter.rs b/tests/ui/coroutine/gen_block_is_fused_iter.rs
new file mode 100644
index 00000000000..f3e19a7f54f
--- /dev/null
+++ b/tests/ui/coroutine/gen_block_is_fused_iter.rs
@@ -0,0 +1,21 @@
+//@ revisions: next old
+//@compile-flags: --edition 2024 -Zunstable-options
+//@[next] compile-flags: -Znext-solver
+//@ check-pass
+#![feature(gen_blocks)]
+
+use std::iter::FusedIterator;
+
+fn foo() -> impl FusedIterator {
+    gen { yield 42 }
+}
+
+fn bar() -> impl FusedIterator<Item = u16> {
+    gen { yield 42 }
+}
+
+fn baz() -> impl FusedIterator + Iterator<Item = i64> {
+    gen { yield 42 }
+}
+
+fn main() {}
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/broken_format.rs b/tests/ui/diagnostic_namespace/on_unimplemented/broken_format.rs
new file mode 100644
index 00000000000..8d8917fd319
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/broken_format.rs
@@ -0,0 +1,45 @@
+#[diagnostic::on_unimplemented(message = "{{Test } thing")]
+//~^WARN unmatched `}` found
+//~|WARN unmatched `}` found
+trait ImportantTrait1 {}
+
+#[diagnostic::on_unimplemented(message = "Test {}")]
+//~^WARN positional format arguments are not allowed here
+//~|WARN positional format arguments are not allowed here
+trait ImportantTrait2 {}
+
+#[diagnostic::on_unimplemented(message = "Test {1:}")]
+//~^WARN positional format arguments are not allowed here
+//~|WARN positional format arguments are not allowed here
+trait ImportantTrait3 {}
+
+#[diagnostic::on_unimplemented(message = "Test {Self:123}")]
+//~^WARN invalid format specifier
+//~|WARN invalid format specifier
+trait ImportantTrait4 {}
+
+#[diagnostic::on_unimplemented(message = "Test {Self:!}")]
+//~^WARN expected `'}'`, found `'!'`
+//~|WARN expected `'}'`, found `'!'`
+//~|WARN unmatched `}` found
+//~|WARN unmatched `}` found
+trait ImportantTrait5 {}
+
+fn check_1(_: impl ImportantTrait1) {}
+fn check_2(_: impl ImportantTrait2) {}
+fn check_3(_: impl ImportantTrait3) {}
+fn check_4(_: impl ImportantTrait4) {}
+fn check_5(_: impl ImportantTrait5) {}
+
+fn main() {
+    check_1(());
+    //~^ERROR {{Test } thing
+    check_2(());
+    //~^ERROR Test {}
+    check_3(());
+    //~^ERROR Test {1}
+    check_4(());
+    //~^ERROR Test ()
+    check_5(());
+    //~^ERROR Test {Self:!}
+}
diff --git a/tests/ui/diagnostic_namespace/on_unimplemented/broken_format.stderr b/tests/ui/diagnostic_namespace/on_unimplemented/broken_format.stderr
new file mode 100644
index 00000000000..932e81ca48e
--- /dev/null
+++ b/tests/ui/diagnostic_namespace/on_unimplemented/broken_format.stderr
@@ -0,0 +1,193 @@
+warning: unmatched `}` found
+  --> $DIR/broken_format.rs:1:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "{{Test } thing")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(unknown_or_malformed_diagnostic_attributes)]` on by default
+
+warning: positional format arguments are not allowed here
+  --> $DIR/broken_format.rs:6:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {}")]
+   |                                ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: only named format arguments with the name of one of the generic types are allowed in this context
+
+warning: positional format arguments are not allowed here
+  --> $DIR/broken_format.rs:11:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {1:}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: only named format arguments with the name of one of the generic types are allowed in this context
+
+warning: invalid format specifier
+  --> $DIR/broken_format.rs:16:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {Self:123}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: no format specifier are supported in this position
+
+warning: expected `'}'`, found `'!'`
+  --> $DIR/broken_format.rs:21:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: unmatched `}` found
+  --> $DIR/broken_format.rs:21:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
+
+warning: unmatched `}` found
+  --> $DIR/broken_format.rs:1:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "{{Test } thing")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0277]: {{Test } thing
+  --> $DIR/broken_format.rs:35:13
+   |
+LL |     check_1(());
+   |     ------- ^^ the trait `ImportantTrait1` is not implemented for `()`
+   |     |
+   |     required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/broken_format.rs:4:1
+   |
+LL | trait ImportantTrait1 {}
+   | ^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `check_1`
+  --> $DIR/broken_format.rs:28:20
+   |
+LL | fn check_1(_: impl ImportantTrait1) {}
+   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_1`
+
+warning: positional format arguments are not allowed here
+  --> $DIR/broken_format.rs:6:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {}")]
+   |                                ^^^^^^^^^^^^^^^^^^^
+   |
+   = help: only named format arguments with the name of one of the generic types are allowed in this context
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0277]: Test {}
+  --> $DIR/broken_format.rs:37:13
+   |
+LL |     check_2(());
+   |     ------- ^^ the trait `ImportantTrait2` is not implemented for `()`
+   |     |
+   |     required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/broken_format.rs:9:1
+   |
+LL | trait ImportantTrait2 {}
+   | ^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `check_2`
+  --> $DIR/broken_format.rs:29:20
+   |
+LL | fn check_2(_: impl ImportantTrait2) {}
+   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_2`
+
+warning: positional format arguments are not allowed here
+  --> $DIR/broken_format.rs:11:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {1:}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: only named format arguments with the name of one of the generic types are allowed in this context
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0277]: Test {1}
+  --> $DIR/broken_format.rs:39:13
+   |
+LL |     check_3(());
+   |     ------- ^^ the trait `ImportantTrait3` is not implemented for `()`
+   |     |
+   |     required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/broken_format.rs:14:1
+   |
+LL | trait ImportantTrait3 {}
+   | ^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `check_3`
+  --> $DIR/broken_format.rs:30:20
+   |
+LL | fn check_3(_: impl ImportantTrait3) {}
+   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_3`
+
+warning: invalid format specifier
+  --> $DIR/broken_format.rs:16:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {Self:123}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: no format specifier are supported in this position
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0277]: Test ()
+  --> $DIR/broken_format.rs:41:13
+   |
+LL |     check_4(());
+   |     ------- ^^ the trait `ImportantTrait4` is not implemented for `()`
+   |     |
+   |     required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/broken_format.rs:19:1
+   |
+LL | trait ImportantTrait4 {}
+   | ^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `check_4`
+  --> $DIR/broken_format.rs:31:20
+   |
+LL | fn check_4(_: impl ImportantTrait4) {}
+   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_4`
+
+warning: expected `'}'`, found `'!'`
+  --> $DIR/broken_format.rs:21:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+warning: unmatched `}` found
+  --> $DIR/broken_format.rs:21:32
+   |
+LL | #[diagnostic::on_unimplemented(message = "Test {Self:!}")]
+   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0277]: Test {Self:!}
+  --> $DIR/broken_format.rs:43:13
+   |
+LL |     check_5(());
+   |     ------- ^^ the trait `ImportantTrait5` is not implemented for `()`
+   |     |
+   |     required by a bound introduced by this call
+   |
+help: this trait has no implementations, consider adding one
+  --> $DIR/broken_format.rs:26:1
+   |
+LL | trait ImportantTrait5 {}
+   | ^^^^^^^^^^^^^^^^^^^^^
+note: required by a bound in `check_5`
+  --> $DIR/broken_format.rs:32:20
+   |
+LL | fn check_5(_: impl ImportantTrait5) {}
+   |                    ^^^^^^^^^^^^^^^ required by this bound in `check_5`
+
+error: aborting due to 5 previous errors; 12 warnings emitted
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/error-codes/E0637.rs b/tests/ui/error-codes/E0637.rs
index e107ea9521b..382ce3ed01f 100644
--- a/tests/ui/error-codes/E0637.rs
+++ b/tests/ui/error-codes/E0637.rs
@@ -2,9 +2,9 @@ fn underscore_lifetime<'_>(str1: &'_ str, str2: &'_ str) -> &'_ str {
     //~^ ERROR: `'_` cannot be used here [E0637]
     //~| ERROR: missing lifetime specifier
     if str1.len() > str2.len() {
-        str1 //~ ERROR: lifetime may not live long enough
+        str1
     } else {
-        str2 //~ ERROR: lifetime may not live long enough
+        str2
     }
 }
 
diff --git a/tests/ui/error-codes/E0637.stderr b/tests/ui/error-codes/E0637.stderr
index 217881b8e7c..d9db89ddb0c 100644
--- a/tests/ui/error-codes/E0637.stderr
+++ b/tests/ui/error-codes/E0637.stderr
@@ -27,25 +27,7 @@ help: consider introducing a higher-ranked lifetime here
 LL |     T: for<'a> Into<&'a u32>,
    |        +++++++       ++
 
-error: lifetime may not live long enough
-  --> $DIR/E0637.rs:5:9
-   |
-LL | fn underscore_lifetime<'_>(str1: &'_ str, str2: &'_ str) -> &'_ str {
-   |                                  - let's call the lifetime of this reference `'1`
-...
-LL |         str1
-   |         ^^^^ returning this value requires that `'1` must outlive `'static`
-
-error: lifetime may not live long enough
-  --> $DIR/E0637.rs:7:9
-   |
-LL | fn underscore_lifetime<'_>(str1: &'_ str, str2: &'_ str) -> &'_ str {
-   |                                                 - let's call the lifetime of this reference `'2`
-...
-LL |         str2
-   |         ^^^^ returning this value requires that `'2` must outlive `'static`
-
-error: aborting due to 5 previous errors
+error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0106, E0637.
 For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/feature-gates/feature-gate-deref_patterns.rs b/tests/ui/feature-gates/feature-gate-deref_patterns.rs
new file mode 100644
index 00000000000..b43001f2d53
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-deref_patterns.rs
@@ -0,0 +1,9 @@
+fn main() {
+    // We reuse the `box` syntax so this doesn't actually test the feature gate but eh.
+    let box x = Box::new('c'); //~ ERROR box pattern syntax is experimental
+    println!("x: {}", x);
+
+    // `box` syntax is allowed to be cfg-ed out for historical reasons (#65742).
+    #[cfg(FALSE)]
+    let box _x = Box::new('c');
+}
diff --git a/tests/ui/feature-gates/feature-gate-deref_patterns.stderr b/tests/ui/feature-gates/feature-gate-deref_patterns.stderr
new file mode 100644
index 00000000000..48426b50d89
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-deref_patterns.stderr
@@ -0,0 +1,13 @@
+error[E0658]: box pattern syntax is experimental
+  --> $DIR/feature-gate-deref_patterns.rs:3:9
+   |
+LL |     let box x = Box::new('c');
+   |         ^^^^^
+   |
+   = note: see issue #29641 <https://github.com/rust-lang/rust/issues/29641> for more information
+   = help: add `#![feature(box_patterns)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/feature-gates/feature-gate-postfix_match.rs b/tests/ui/feature-gates/feature-gate-postfix_match.rs
new file mode 100644
index 00000000000..dce7e81a9ae
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-postfix_match.rs
@@ -0,0 +1,17 @@
+// Testing that postfix match doesn't work without enabling the feature
+
+fn main() {
+    let val = Some(42);
+
+    val.match { //~ ERROR postfix match is experimental
+        Some(42) => "the answer to life, the universe, and everything",
+        _ => "might be the answer to something"
+    };
+
+    // Test that the gate works behind a cfg
+    #[cfg(FALSE)]
+    val.match { //~ ERROR postfix match is experimental
+        Some(42) => "the answer to life, the universe, and everything",
+        _ => "might be the answer to something"
+    };
+}
diff --git a/tests/ui/feature-gates/feature-gate-postfix_match.stderr b/tests/ui/feature-gates/feature-gate-postfix_match.stderr
new file mode 100644
index 00000000000..136838788dd
--- /dev/null
+++ b/tests/ui/feature-gates/feature-gate-postfix_match.stderr
@@ -0,0 +1,23 @@
+error[E0658]: postfix match is experimental
+  --> $DIR/feature-gate-postfix_match.rs:6:9
+   |
+LL |     val.match {
+   |         ^^^^^
+   |
+   = note: see issue #121618 <https://github.com/rust-lang/rust/issues/121618> for more information
+   = help: add `#![feature(postfix_match)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error[E0658]: postfix match is experimental
+  --> $DIR/feature-gate-postfix_match.rs:13:9
+   |
+LL |     val.match {
+   |         ^^^^^
+   |
+   = note: see issue #121618 <https://github.com/rust-lang/rust/issues/121618> for more information
+   = help: add `#![feature(postfix_match)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/generic-associated-types/issue-102335-gat.rs b/tests/ui/generic-associated-types/issue-102335-gat.rs
index a7255fdcbf5..3a4a0c10771 100644
--- a/tests/ui/generic-associated-types/issue-102335-gat.rs
+++ b/tests/ui/generic-associated-types/issue-102335-gat.rs
@@ -1,6 +1,7 @@
 trait T {
     type A: S<C<(), i32 = ()> = ()>;
     //~^ ERROR associated type bindings are not allowed here
+    //~| ERROR associated type bindings are not allowed here
 }
 
 trait Q {}
diff --git a/tests/ui/generic-associated-types/issue-102335-gat.stderr b/tests/ui/generic-associated-types/issue-102335-gat.stderr
index 39ca7954ede..f5e782e92fc 100644
--- a/tests/ui/generic-associated-types/issue-102335-gat.stderr
+++ b/tests/ui/generic-associated-types/issue-102335-gat.stderr
@@ -4,6 +4,14 @@ error[E0229]: associated type bindings are not allowed here
 LL |     type A: S<C<(), i32 = ()> = ()>;
    |                     ^^^^^^^^ associated type not allowed here
 
-error: aborting due to 1 previous error
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/issue-102335-gat.rs:2:21
+   |
+LL |     type A: S<C<(), i32 = ()> = ()>;
+   |                     ^^^^^^^^ associated type not allowed here
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/ui/generic-associated-types/issue-80433.rs b/tests/ui/generic-associated-types/issue-80433.rs
index 6d23427f16f..53057542440 100644
--- a/tests/ui/generic-associated-types/issue-80433.rs
+++ b/tests/ui/generic-associated-types/issue-80433.rs
@@ -29,5 +29,5 @@ fn test_simpler<'a>(dst: &'a mut impl TestMut<Output = &'a mut f32>)
 
 fn main() {
     let mut t1: E<f32> = Default::default();
-    test_simpler(&mut t1); //~ ERROR does not live long enough
+    test_simpler(&mut t1);
 }
diff --git a/tests/ui/generic-associated-types/issue-80433.stderr b/tests/ui/generic-associated-types/issue-80433.stderr
index 1ca080f5df2..a9a14d3f51c 100644
--- a/tests/ui/generic-associated-types/issue-80433.stderr
+++ b/tests/ui/generic-associated-types/issue-80433.stderr
@@ -48,20 +48,7 @@ LL |         *dst.test_mut() = n.into();
    |          `dst` escapes the function body here
    |          argument requires that `'a` must outlive `'static`
 
-error[E0597]: `t1` does not live long enough
-  --> $DIR/issue-80433.rs:32:18
-   |
-LL |     let mut t1: E<f32> = Default::default();
-   |         ------ binding `t1` declared here
-LL |     test_simpler(&mut t1);
-   |     -------------^^^^^^^-
-   |     |            |
-   |     |            borrowed value does not live long enough
-   |     argument requires that `t1` is borrowed for `'static`
-LL | }
-   | - `t1` dropped here while still borrowed
-
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0107, E0499, E0521, E0597.
+Some errors have detailed explanations: E0107, E0499, E0521.
 For more information about an error, try `rustc --explain E0107`.
diff --git a/tests/ui/generic-associated-types/issue-81712-cyclic-traits.rs b/tests/ui/generic-associated-types/issue-81712-cyclic-traits.rs
index a7cc9a6053e..412eeb6e29a 100644
--- a/tests/ui/generic-associated-types/issue-81712-cyclic-traits.rs
+++ b/tests/ui/generic-associated-types/issue-81712-cyclic-traits.rs
@@ -13,6 +13,7 @@ trait C {
 trait D<T> {
     type CType: C<DType = Self>;
     //~^ ERROR missing generics for associated type
+    //~| ERROR missing generics for associated type
 }
 
 fn main() {}
diff --git a/tests/ui/generic-associated-types/issue-81712-cyclic-traits.stderr b/tests/ui/generic-associated-types/issue-81712-cyclic-traits.stderr
index 5eb988ea042..33c40f88f87 100644
--- a/tests/ui/generic-associated-types/issue-81712-cyclic-traits.stderr
+++ b/tests/ui/generic-associated-types/issue-81712-cyclic-traits.stderr
@@ -14,6 +14,23 @@ help: add missing generic argument
 LL |     type CType: C<DType<T> = Self>;
    |                        +++
 
-error: aborting due to 1 previous error
+error[E0107]: missing generics for associated type `C::DType`
+  --> $DIR/issue-81712-cyclic-traits.rs:14:19
+   |
+LL |     type CType: C<DType = Self>;
+   |                   ^^^^^ expected 1 generic argument
+   |
+note: associated type defined here, with 1 generic parameter: `T`
+  --> $DIR/issue-81712-cyclic-traits.rs:11:10
+   |
+LL |     type DType<T>: D<T, CType = Self>;
+   |          ^^^^^ -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add missing generic argument
+   |
+LL |     type CType: C<DType<T> = Self>;
+   |                        +++
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0107`.
diff --git a/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.rs b/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.rs
index 41c5b9f5074..e75cfc88ef4 100644
--- a/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.rs
+++ b/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.rs
@@ -5,6 +5,8 @@
 fn ice() -> impl AsRef<Fn(&())> {
     //~^ WARN trait objects without an explicit `dyn` are deprecated
     //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+    //~| WARN trait objects without an explicit `dyn` are deprecated
+    //~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
     Foo
 }
 
diff --git a/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.stderr b/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.stderr
index 3cb3af89bfc..d82b2c0f606 100644
--- a/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.stderr
+++ b/tests/ui/impl-trait/fresh-lifetime-from-bare-trait-obj-114664.stderr
@@ -12,5 +12,19 @@ help: if this is an object-safe trait, use `dyn`
 LL | fn ice() -> impl AsRef<dyn Fn(&())> {
    |                        +++
 
-warning: 1 warning emitted
+warning: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/fresh-lifetime-from-bare-trait-obj-114664.rs:5:24
+   |
+LL | fn ice() -> impl AsRef<Fn(&())> {
+   |                        ^^^^^^^
+   |
+   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: if this is an object-safe trait, use `dyn`
+   |
+LL | fn ice() -> impl AsRef<dyn Fn(&())> {
+   |                        +++
+
+warning: 2 warnings emitted
 
diff --git a/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs b/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs
index a9ea657f10e..da7530b4e7a 100644
--- a/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs
+++ b/tests/ui/impl-trait/impl-fn-hrtb-bounds.rs
@@ -4,19 +4,16 @@ use std::fmt::Debug;
 fn a() -> impl Fn(&u8) -> (impl Debug + '_) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
     //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn d() -> impl Fn() -> (impl Debug + '_) {
diff --git a/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr b/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr
index bdb099619b7..7d108b30b76 100644
--- a/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr
+++ b/tests/ui/impl-trait/impl-fn-hrtb-bounds.stderr
@@ -1,5 +1,5 @@
 error[E0106]: missing lifetime specifier
-  --> $DIR/impl-fn-hrtb-bounds.rs:22:38
+  --> $DIR/impl-fn-hrtb-bounds.rs:19:38
    |
 LL | fn d() -> impl Fn() -> (impl Debug + '_) {
    |                                      ^^ expected named lifetime parameter
@@ -22,58 +22,31 @@ note: lifetime declared here
 LL | fn a() -> impl Fn(&u8) -> (impl Debug + '_) {
    |                   ^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-hrtb-bounds.rs:6:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
 error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
-  --> $DIR/impl-fn-hrtb-bounds.rs:10:52
+  --> $DIR/impl-fn-hrtb-bounds.rs:9:52
    |
 LL | fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
    |                                                    ^^
    |
 note: lifetime declared here
-  --> $DIR/impl-fn-hrtb-bounds.rs:10:20
+  --> $DIR/impl-fn-hrtb-bounds.rs:9:20
    |
 LL | fn b() -> impl for<'a> Fn(&'a u8) -> (impl Debug + 'a) {
    |                    ^^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-hrtb-bounds.rs:12:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
 error[E0657]: `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
-  --> $DIR/impl-fn-hrtb-bounds.rs:16:52
+  --> $DIR/impl-fn-hrtb-bounds.rs:14:52
    |
 LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
    |                                                    ^^
    |
 note: lifetime declared here
-  --> $DIR/impl-fn-hrtb-bounds.rs:16:20
+  --> $DIR/impl-fn-hrtb-bounds.rs:14:20
    |
 LL | fn c() -> impl for<'a> Fn(&'a u8) -> (impl Debug + '_) {
    |                    ^^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-hrtb-bounds.rs:18:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
-error: aborting due to 7 previous errors
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0106, E0657.
 For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs
index ef9d8733509..7679b7ec478 100644
--- a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs
+++ b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.rs
@@ -5,7 +5,6 @@ fn a() -> impl Fn(&u8) -> impl Debug + '_ {
     //~^ ERROR ambiguous `+` in a type
     //~| ERROR cannot capture higher-ranked lifetime from outer `impl Trait`
     |x| x
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn b() -> impl Fn() -> impl Debug + Send {
diff --git a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr
index 3881b37a0cb..e0955faac7c 100644
--- a/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr
+++ b/tests/ui/impl-trait/impl-fn-parsing-ambiguities.stderr
@@ -5,7 +5,7 @@ LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
    |                           ^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + '_)`
 
 error: ambiguous `+` in a type
-  --> $DIR/impl-fn-parsing-ambiguities.rs:11:24
+  --> $DIR/impl-fn-parsing-ambiguities.rs:10:24
    |
 LL | fn b() -> impl Fn() -> impl Debug + Send {
    |                        ^^^^^^^^^^^^^^^^^ help: use parentheses to disambiguate: `(impl Debug + Send)`
@@ -22,15 +22,6 @@ note: lifetime declared here
 LL | fn a() -> impl Fn(&u8) -> impl Debug + '_ {
    |                   ^
 
-error: lifetime may not live long enough
-  --> $DIR/impl-fn-parsing-ambiguities.rs:7:9
-   |
-LL |     |x| x
-   |      -- ^ returning this value requires that `'1` must outlive `'2`
-   |      ||
-   |      |return type of closure is impl Debug + '2
-   |      has type `&'1 u8`
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0657`.
diff --git a/tests/ui/impl-trait/in-trait/span-bug-issue-121457.rs b/tests/ui/impl-trait/in-trait/span-bug-issue-121457.rs
index 10167ee9352..ab21dae7dc5 100644
--- a/tests/ui/impl-trait/in-trait/span-bug-issue-121457.rs
+++ b/tests/ui/impl-trait/in-trait/span-bug-issue-121457.rs
@@ -12,6 +12,7 @@ impl<'a, I: 'a + Iterable> Iterable for &'a I {
 
     fn iter(&self) -> impl for<'missing> Iterator<Item = Self::Item<'missing>> {}
     //~^ ERROR binding for associated type `Item` references lifetime `'missing`
+    //~| ERROR binding for associated type `Item` references lifetime `'missing`
     //~| ERROR `()` is not an iterator
 }
 
diff --git a/tests/ui/impl-trait/in-trait/span-bug-issue-121457.stderr b/tests/ui/impl-trait/in-trait/span-bug-issue-121457.stderr
index 96c3644f893..d8a2eef94a1 100644
--- a/tests/ui/impl-trait/in-trait/span-bug-issue-121457.stderr
+++ b/tests/ui/impl-trait/in-trait/span-bug-issue-121457.stderr
@@ -4,6 +4,14 @@ error[E0582]: binding for associated type `Item` references lifetime `'missing`,
 LL |     fn iter(&self) -> impl for<'missing> Iterator<Item = Self::Item<'missing>> {}
    |                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+error[E0582]: binding for associated type `Item` references lifetime `'missing`, which does not appear in the trait input types
+  --> $DIR/span-bug-issue-121457.rs:13:51
+   |
+LL |     fn iter(&self) -> impl for<'missing> Iterator<Item = Self::Item<'missing>> {}
+   |                                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error[E0195]: lifetime parameters or bounds on type `Item` do not match the trait declaration
   --> $DIR/span-bug-issue-121457.rs:10:14
    |
@@ -24,7 +32,7 @@ LL |     fn iter(&self) -> impl for<'missing> Iterator<Item = Self::Item<'missin
    |
    = help: the trait `Iterator` is not implemented for `()`
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0195, E0277, E0582.
 For more information about an error, try `rustc --explain E0195`.
diff --git a/tests/ui/impl-trait/issues/issue-92305.rs b/tests/ui/impl-trait/issues/issue-92305.rs
index 5ecb6984cfe..be98ce807ec 100644
--- a/tests/ui/impl-trait/issues/issue-92305.rs
+++ b/tests/ui/impl-trait/issues/issue-92305.rs
@@ -4,6 +4,7 @@ use std::iter;
 
 fn f<T>(data: &[T]) -> impl Iterator<Item = Vec> {
     //~^ ERROR: missing generics for struct `Vec` [E0107]
+    //~| ERROR: missing generics for struct `Vec` [E0107]
     iter::empty()
 }
 
diff --git a/tests/ui/impl-trait/issues/issue-92305.stderr b/tests/ui/impl-trait/issues/issue-92305.stderr
index 88fb1fb2707..4591d2c53f7 100644
--- a/tests/ui/impl-trait/issues/issue-92305.stderr
+++ b/tests/ui/impl-trait/issues/issue-92305.stderr
@@ -9,6 +9,18 @@ help: add missing generic argument
 LL | fn f<T>(data: &[T]) -> impl Iterator<Item = Vec<T>> {
    |                                                +++
 
-error: aborting due to 1 previous error
+error[E0107]: missing generics for struct `Vec`
+  --> $DIR/issue-92305.rs:5:45
+   |
+LL | fn f<T>(data: &[T]) -> impl Iterator<Item = Vec> {
+   |                                             ^^^ expected at least 1 generic argument
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add missing generic argument
+   |
+LL | fn f<T>(data: &[T]) -> impl Iterator<Item = Vec<T>> {
+   |                                                +++
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0107`.
diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.rs b/tests/ui/impl-trait/nested-rpit-hrtb.rs
index c10bfbfe4dc..a696e1710f0 100644
--- a/tests/ui/impl-trait/nested-rpit-hrtb.rs
+++ b/tests/ui/impl-trait/nested-rpit-hrtb.rs
@@ -35,7 +35,6 @@ fn one_hrtb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'a> {}
 
 fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
 //~^ ERROR `impl Trait` cannot capture higher-ranked lifetime from outer `impl Trait`
-//~| ERROR: the trait bound `for<'a> &'a (): Qux<'_>` is not satisfied
 
 // This should resolve.
 fn one_hrtb_mention_fn_trait_param<'b>() -> impl for<'a> Foo<'a, Assoc = impl Qux<'b>> {}
@@ -45,7 +44,7 @@ fn one_hrtb_mention_fn_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl Sized
 
 // This should resolve.
 fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Qux<'b>> {}
-//~^ ERROR: the trait bound `for<'a> &'a (): Qux<'b>` is not satisfied
+//~^ ERROR type annotations needed: cannot satisfy `for<'a> &'a (): Qux<'b>`
 
 // This should resolve.
 fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {}
diff --git a/tests/ui/impl-trait/nested-rpit-hrtb.stderr b/tests/ui/impl-trait/nested-rpit-hrtb.stderr
index 2779694a517..64f801ea685 100644
--- a/tests/ui/impl-trait/nested-rpit-hrtb.stderr
+++ b/tests/ui/impl-trait/nested-rpit-hrtb.stderr
@@ -1,5 +1,5 @@
 error[E0261]: use of undeclared lifetime name `'b`
-  --> $DIR/nested-rpit-hrtb.rs:58:77
+  --> $DIR/nested-rpit-hrtb.rs:57:77
    |
 LL | fn two_htrb_outlives() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Sized + 'b> {}
    |                                                                             ^^ undeclared lifetime
@@ -15,7 +15,7 @@ LL | fn two_htrb_outlives<'b>() -> impl for<'a> Foo<'a, Assoc = impl for<'b> Siz
    |                     ++++
 
 error[E0261]: use of undeclared lifetime name `'b`
-  --> $DIR/nested-rpit-hrtb.rs:66:82
+  --> $DIR/nested-rpit-hrtb.rs:65:82
    |
 LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {}
    |                                                                                  ^^ undeclared lifetime
@@ -86,26 +86,18 @@ note: lifetime declared here
 LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
    |                                            ^^
 
-error[E0277]: the trait bound `for<'a> &'a (): Qux<'_>` is not satisfied
-  --> $DIR/nested-rpit-hrtb.rs:36:64
-   |
-LL | fn one_hrtb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl Qux<'a>> {}
-   |                                                                ^^^^^^^^^^^^ the trait `for<'a> Qux<'_>` is not implemented for `&'a ()`
-   |
-   = help: the trait `Qux<'_>` is implemented for `()`
-   = help: for that trait implementation, expected `()`, found `&'a ()`
-
-error[E0277]: the trait bound `for<'a> &'a (): Qux<'b>` is not satisfied
-  --> $DIR/nested-rpit-hrtb.rs:47:79
+error[E0283]: type annotations needed: cannot satisfy `for<'a> &'a (): Qux<'b>`
+  --> $DIR/nested-rpit-hrtb.rs:46:79
    |
 LL | fn one_hrtb_mention_fn_trait_param_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Qux<'b>> {}
-   |                                                                               ^^^^^^^^^^^^ the trait `for<'a> Qux<'b>` is not implemented for `&'a ()`
+   |                                                                               ^^^^^^^^^^^^
    |
+   = note: cannot satisfy `for<'a> &'a (): Qux<'b>`
    = help: the trait `Qux<'_>` is implemented for `()`
    = help: for that trait implementation, expected `()`, found `&'a ()`
 
 error: implementation of `Bar` is not general enough
-  --> $DIR/nested-rpit-hrtb.rs:51:93
+  --> $DIR/nested-rpit-hrtb.rs:50:93
    |
 LL | fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc = impl Sized + 'b> {}
    |                                                                                             ^^ implementation of `Bar` is not general enough
@@ -114,7 +106,7 @@ LL | fn one_hrtb_mention_fn_outlives_uses<'b>() -> impl for<'a> Bar<'a, Assoc =
    = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0`
 
 error[E0277]: the trait bound `for<'a, 'b> &'a (): Qux<'b>` is not satisfied
-  --> $DIR/nested-rpit-hrtb.rs:62:64
+  --> $DIR/nested-rpit-hrtb.rs:61:64
    |
 LL | fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Qux<'b>> {}
    |                                                                ^^^^^^^^^^^^^^^^^^^^ the trait `for<'a, 'b> Qux<'b>` is not implemented for `&'a ()`
@@ -123,7 +115,7 @@ LL | fn two_htrb_trait_param_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b>
    = help: for that trait implementation, expected `()`, found `&'a ()`
 
 error: implementation of `Bar` is not general enough
-  --> $DIR/nested-rpit-hrtb.rs:66:86
+  --> $DIR/nested-rpit-hrtb.rs:65:86
    |
 LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Sized + 'b> {}
    |                                                                                      ^^ implementation of `Bar` is not general enough
@@ -131,7 +123,7 @@ LL | fn two_htrb_outlives_uses() -> impl for<'a> Bar<'a, Assoc = impl for<'b> Si
    = note: `()` must implement `Bar<'a>`
    = note: ...but it actually implements `Bar<'0>`, for some specific lifetime `'0`
 
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors
 
-Some errors have detailed explanations: E0261, E0277, E0657.
+Some errors have detailed explanations: E0261, E0277, E0283, E0657.
 For more information about an error, try `rustc --explain E0261`.
diff --git a/tests/ui/impl-trait/opaque-used-in-extraneous-argument.rs b/tests/ui/impl-trait/opaque-used-in-extraneous-argument.rs
index 529913479ef..8d4855c101c 100644
--- a/tests/ui/impl-trait/opaque-used-in-extraneous-argument.rs
+++ b/tests/ui/impl-trait/opaque-used-in-extraneous-argument.rs
@@ -7,6 +7,7 @@ fn frob() -> impl Fn<P, Output = T> + '_ {}
 //~| ERROR cannot find type `P`
 //~| ERROR cannot find type `T`
 //~| ERROR `Fn`-family traits' type parameters is subject to change
+//~| ERROR `Fn`-family traits' type parameters is subject to change
 
 fn open_parent<'path>() {
     todo!()
diff --git a/tests/ui/impl-trait/opaque-used-in-extraneous-argument.stderr b/tests/ui/impl-trait/opaque-used-in-extraneous-argument.stderr
index b54b9f908b2..6d417488533 100644
--- a/tests/ui/impl-trait/opaque-used-in-extraneous-argument.stderr
+++ b/tests/ui/impl-trait/opaque-used-in-extraneous-argument.stderr
@@ -42,8 +42,19 @@ LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
    = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
+error[E0658]: the precise format of `Fn`-family traits' type parameters is subject to change
+  --> $DIR/opaque-used-in-extraneous-argument.rs:5:19
+   |
+LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
+   |                   ^^^^^^^^^^^^^^^^^ help: use parenthetical notation instead: `Fn(P) -> T`
+   |
+   = note: see issue #29625 <https://github.com/rust-lang/rust/issues/29625> for more information
+   = help: add `#![feature(unboxed_closures)]` to the crate attributes to enable
+   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error[E0061]: this function takes 0 arguments but 1 argument was supplied
-  --> $DIR/opaque-used-in-extraneous-argument.rs:16:20
+  --> $DIR/opaque-used-in-extraneous-argument.rs:17:20
    |
 LL |     let old_path = frob("hello");
    |                    ^^^^ -------
@@ -58,7 +69,7 @@ LL | fn frob() -> impl Fn<P, Output = T> + '_ {}
    |    ^^^^
 
 error[E0061]: this function takes 0 arguments but 1 argument was supplied
-  --> $DIR/opaque-used-in-extraneous-argument.rs:19:5
+  --> $DIR/opaque-used-in-extraneous-argument.rs:20:5
    |
 LL |     open_parent(&old_path)
    |     ^^^^^^^^^^^ ---------
@@ -67,12 +78,12 @@ LL |     open_parent(&old_path)
    |                 help: remove the extra argument
    |
 note: function defined here
-  --> $DIR/opaque-used-in-extraneous-argument.rs:11:4
+  --> $DIR/opaque-used-in-extraneous-argument.rs:12:4
    |
 LL | fn open_parent<'path>() {
    |    ^^^^^^^^^^^
 
-error: aborting due to 6 previous errors
+error: aborting due to 7 previous errors
 
 Some errors have detailed explanations: E0061, E0106, E0412, E0658.
 For more information about an error, try `rustc --explain E0061`.
diff --git a/tests/ui/impl-trait/stranded-opaque.rs b/tests/ui/impl-trait/stranded-opaque.rs
index c7ab390e1fd..6ce5cbd3b55 100644
--- a/tests/ui/impl-trait/stranded-opaque.rs
+++ b/tests/ui/impl-trait/stranded-opaque.rs
@@ -7,6 +7,7 @@ impl Trait for i32 {}
 // ICE in this case.
 fn produce<T>() -> impl Trait<Assoc = impl Trait> {
     //~^ ERROR associated type `Assoc` not found for `Trait`
+    //~| ERROR associated type `Assoc` not found for `Trait`
     16
 }
 
diff --git a/tests/ui/impl-trait/stranded-opaque.stderr b/tests/ui/impl-trait/stranded-opaque.stderr
index 75f5480bc8b..5bea3e2af6b 100644
--- a/tests/ui/impl-trait/stranded-opaque.stderr
+++ b/tests/ui/impl-trait/stranded-opaque.stderr
@@ -4,6 +4,14 @@ error[E0220]: associated type `Assoc` not found for `Trait`
 LL | fn produce<T>() -> impl Trait<Assoc = impl Trait> {
    |                               ^^^^^ associated type `Assoc` not found
 
-error: aborting due to 1 previous error
+error[E0220]: associated type `Assoc` not found for `Trait`
+  --> $DIR/stranded-opaque.rs:8:31
+   |
+LL | fn produce<T>() -> impl Trait<Assoc = impl Trait> {
+   |                               ^^^^^ associated type `Assoc` not found
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/ui/inference/ice-cannot-relate-region-109178.rs b/tests/ui/inference/ice-cannot-relate-region-109178.rs
new file mode 100644
index 00000000000..3282f95a992
--- /dev/null
+++ b/tests/ui/inference/ice-cannot-relate-region-109178.rs
@@ -0,0 +1,14 @@
+// test for ice #109178  cannot relate region: LUB(ReErased, ReError)
+
+#![allow(incomplete_features)]
+#![crate_type = "lib"]
+#![feature(adt_const_params, generic_const_exprs)]
+
+struct Changes<const CHANGES: &[&'static str]>
+//~^ ERROR `&` without an explicit lifetime name cannot be used here
+where
+    [(); CHANGES.len()]:, {}
+
+impl<const CHANGES: &[&str]> Changes<CHANGES> where [(); CHANGES.len()]: {}
+//~^ ERROR `&` without an explicit lifetime name cannot be used here
+//~^^ ERROR `&` without an explicit lifetime name cannot be used here
diff --git a/tests/ui/inference/ice-cannot-relate-region-109178.stderr b/tests/ui/inference/ice-cannot-relate-region-109178.stderr
new file mode 100644
index 00000000000..0ac924452c0
--- /dev/null
+++ b/tests/ui/inference/ice-cannot-relate-region-109178.stderr
@@ -0,0 +1,21 @@
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/ice-cannot-relate-region-109178.rs:7:31
+   |
+LL | struct Changes<const CHANGES: &[&'static str]>
+   |                               ^ explicit lifetime name needed here
+
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/ice-cannot-relate-region-109178.rs:12:21
+   |
+LL | impl<const CHANGES: &[&str]> Changes<CHANGES> where [(); CHANGES.len()]: {}
+   |                     ^ explicit lifetime name needed here
+
+error[E0637]: `&` without an explicit lifetime name cannot be used here
+  --> $DIR/ice-cannot-relate-region-109178.rs:12:23
+   |
+LL | impl<const CHANGES: &[&str]> Changes<CHANGES> where [(); CHANGES.len()]: {}
+   |                       ^ explicit lifetime name needed here
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0637`.
diff --git a/tests/ui/inference/ice-ifer-var-leaked-out-of-rollback-122098.rs b/tests/ui/inference/ice-ifer-var-leaked-out-of-rollback-122098.rs
new file mode 100644
index 00000000000..3c2aa176c0f
--- /dev/null
+++ b/tests/ui/inference/ice-ifer-var-leaked-out-of-rollback-122098.rs
@@ -0,0 +1,25 @@
+// test for #122098 ICE snapshot_vec.rs: index out of bounds: the len is 4 but the index is 4
+
+trait LendingIterator {
+    type Item<'q>: 'a;
+    //~^ ERROR use of undeclared lifetime name `'a`
+
+    fn for_each(mut self, mut f: Box<dyn FnMut(Self::Item<'_>) + 'static>) {}
+    //~^ ERROR the size for values of type `Self` cannot be known at compilation time
+}
+
+struct Query<'q> {}
+//~^ ERROR lifetime parameter `'q` is never used
+
+impl<'static> Query<'q> {
+//~^ ERROR invalid lifetime parameter name: `'static`
+//~^^ ERROR use of undeclared lifetime name `'q`
+    pub fn new() -> Self {}
+}
+
+fn data() {
+    LendingIterator::for_each(Query::new(&data), Box::new);
+    //~^ ERROR this function takes 0 arguments but 1 argument was supplied
+}
+
+pub fn main() {}
diff --git a/tests/ui/inference/ice-ifer-var-leaked-out-of-rollback-122098.stderr b/tests/ui/inference/ice-ifer-var-leaked-out-of-rollback-122098.stderr
new file mode 100644
index 00000000000..e2ddf474c4a
--- /dev/null
+++ b/tests/ui/inference/ice-ifer-var-leaked-out-of-rollback-122098.stderr
@@ -0,0 +1,72 @@
+error[E0261]: use of undeclared lifetime name `'a`
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:4:20
+   |
+LL |     type Item<'q>: 'a;
+   |                    ^^ undeclared lifetime
+   |
+help: consider introducing lifetime `'a` here
+   |
+LL |     type Item<'a, 'q>: 'a;
+   |               +++
+help: consider introducing lifetime `'a` here
+   |
+LL | trait LendingIterator<'a> {
+   |                      ++++
+
+error[E0262]: invalid lifetime parameter name: `'static`
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:14:6
+   |
+LL | impl<'static> Query<'q> {
+   |      ^^^^^^^ 'static is a reserved lifetime name
+
+error[E0261]: use of undeclared lifetime name `'q`
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:14:21
+   |
+LL | impl<'static> Query<'q> {
+   |      -              ^^ undeclared lifetime
+   |      |
+   |      help: consider introducing lifetime `'q` here: `'q,`
+
+error[E0392]: lifetime parameter `'q` is never used
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:11:14
+   |
+LL | struct Query<'q> {}
+   |              ^^ unused lifetime parameter
+   |
+   = help: consider removing `'q`, referring to it in a field, or using a marker such as `PhantomData`
+
+error[E0277]: the size for values of type `Self` cannot be known at compilation time
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:7:17
+   |
+LL |     fn for_each(mut self, mut f: Box<dyn FnMut(Self::Item<'_>) + 'static>) {}
+   |                 ^^^^^^^^ doesn't have a size known at compile-time
+   |
+   = help: unsized fn params are gated as an unstable feature
+help: consider further restricting `Self`
+   |
+LL |     fn for_each(mut self, mut f: Box<dyn FnMut(Self::Item<'_>) + 'static>) where Self: Sized {}
+   |                                                                            +++++++++++++++++
+help: function arguments must have a statically known size, borrowed types always have a known size
+   |
+LL |     fn for_each(mut &self, mut f: Box<dyn FnMut(Self::Item<'_>) + 'static>) {}
+   |                     +
+
+error[E0061]: this function takes 0 arguments but 1 argument was supplied
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:21:31
+   |
+LL |     LendingIterator::for_each(Query::new(&data), Box::new);
+   |                               ^^^^^^^^^^ -----
+   |                                          |
+   |                                          unexpected argument of type `&fn() {data}`
+   |                                          help: remove the extra argument
+   |
+note: associated function defined here
+  --> $DIR/ice-ifer-var-leaked-out-of-rollback-122098.rs:17:12
+   |
+LL |     pub fn new() -> Self {}
+   |            ^^^
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0061, E0261, E0262, E0277, E0392.
+For more information about an error, try `rustc --explain E0061`.
diff --git a/tests/ui/inference/issue-107090.rs b/tests/ui/inference/issue-107090.rs
index d1c86fb03d7..799c3641833 100644
--- a/tests/ui/inference/issue-107090.rs
+++ b/tests/ui/inference/issue-107090.rs
@@ -19,7 +19,7 @@ impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
 
 fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
     //~^ ERROR use of undeclared lifetime name
-    sadness.cast() //~ ERROR: mismatched types
+    sadness.cast()
 }
 
 fn main() {}
diff --git a/tests/ui/inference/issue-107090.stderr b/tests/ui/inference/issue-107090.stderr
index 55825f7765b..e509e262fb1 100644
--- a/tests/ui/inference/issue-107090.stderr
+++ b/tests/ui/inference/issue-107090.stderr
@@ -66,19 +66,6 @@ LL | fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short,
    |           |
    |           help: consider introducing lifetime `'short` here: `'short,`
 
-error[E0308]: mismatched types
-  --> $DIR/issue-107090.rs:22:5
-   |
-LL | fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
-   |                       - expected this type parameter                                    ------- expected `&'out T` because of return type
-LL |
-LL |     sadness.cast()
-   |     ^^^^^^^^^^^^^^ expected `&T`, found `&Foo<'_, '_, T>`
-   |
-   = note: expected reference `&'out T`
-              found reference `&Foo<'_, '_, T>`
-
-error: aborting due to 7 previous errors
+error: aborting due to 6 previous errors
 
-Some errors have detailed explanations: E0261, E0308.
-For more information about an error, try `rustc --explain E0261`.
+For more information about this error, try `rustc --explain E0261`.
diff --git a/tests/ui/issues/issue-10412.rs b/tests/ui/issues/issue-10412.rs
index 0de170161b5..68ce0c2ea3c 100644
--- a/tests/ui/issues/issue-10412.rs
+++ b/tests/ui/issues/issue-10412.rs
@@ -8,7 +8,6 @@ impl<'self> Serializable<str> for &'self str {
     //~^ ERROR lifetimes cannot use keyword names
     //~| ERROR lifetimes cannot use keyword names
     //~| ERROR implicit elided lifetime not allowed here
-    //~| ERROR the size for values of type `str` cannot be known at compilation time [E0277]
     fn serialize(val: &'self str) -> Vec<u8> {
         //~^ ERROR lifetimes cannot use keyword names
         vec![1]
diff --git a/tests/ui/issues/issue-10412.stderr b/tests/ui/issues/issue-10412.stderr
index 02a26034f9a..c74ba1306cc 100644
--- a/tests/ui/issues/issue-10412.stderr
+++ b/tests/ui/issues/issue-10412.stderr
@@ -29,13 +29,13 @@ LL | impl<'self> Serializable<str> for &'self str {
    |                                    ^^^^^
 
 error: lifetimes cannot use keyword names
-  --> $DIR/issue-10412.rs:12:24
+  --> $DIR/issue-10412.rs:11:24
    |
 LL |     fn serialize(val: &'self str) -> Vec<u8> {
    |                        ^^^^^
 
 error: lifetimes cannot use keyword names
-  --> $DIR/issue-10412.rs:16:37
+  --> $DIR/issue-10412.rs:15:37
    |
 LL |     fn deserialize(repr: &[u8]) -> &'self str {
    |                                     ^^^^^
@@ -51,24 +51,6 @@ help: indicate the anonymous lifetime
 LL | impl<'self> Serializable<'_, str> for &'self str {
    |                          +++
 
-error[E0277]: the size for values of type `str` cannot be known at compilation time
-  --> $DIR/issue-10412.rs:7:13
-   |
-LL | impl<'self> Serializable<str> for &'self str {
-   |             ^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time
-   |
-   = help: the trait `Sized` is not implemented for `str`
-note: required by an implicit `Sized` bound in `Serializable`
-  --> $DIR/issue-10412.rs:1:27
-   |
-LL | trait Serializable<'self, T> {
-   |                           ^ required by the implicit `Sized` requirement on this type parameter in `Serializable`
-help: consider relaxing the implicit `Sized` restriction
-   |
-LL | trait Serializable<'self, T: ?Sized> {
-   |                            ++++++++
-
-error: aborting due to 9 previous errors
+error: aborting due to 8 previous errors
 
-Some errors have detailed explanations: E0277, E0726.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0726`.
diff --git a/tests/ui/issues/issue-27942.stderr b/tests/ui/issues/issue-27942.stderr
index 7ea9345a668..8ea46bae26d 100644
--- a/tests/ui/issues/issue-27942.stderr
+++ b/tests/ui/issues/issue-27942.stderr
@@ -6,16 +6,16 @@ LL |     fn select(&self) -> BufferViewHandle<R>;
    |
    = note: expected trait `Resources<'_>`
               found trait `Resources<'a>`
-note: the anonymous lifetime defined here...
-  --> $DIR/issue-27942.rs:5:15
-   |
-LL |     fn select(&self) -> BufferViewHandle<R>;
-   |               ^^^^^
-note: ...does not necessarily outlive the lifetime `'a` as defined here
+note: the lifetime `'a` as defined here...
   --> $DIR/issue-27942.rs:3:18
    |
 LL | pub trait Buffer<'a, R: Resources<'a>> {
    |                  ^^
+note: ...does not necessarily outlive the anonymous lifetime defined here
+  --> $DIR/issue-27942.rs:5:15
+   |
+LL |     fn select(&self) -> BufferViewHandle<R>;
+   |               ^^^^^
 
 error[E0308]: mismatched types
   --> $DIR/issue-27942.rs:5:25
@@ -25,16 +25,16 @@ LL |     fn select(&self) -> BufferViewHandle<R>;
    |
    = note: expected trait `Resources<'_>`
               found trait `Resources<'a>`
-note: the lifetime `'a` as defined here...
-  --> $DIR/issue-27942.rs:3:18
-   |
-LL | pub trait Buffer<'a, R: Resources<'a>> {
-   |                  ^^
-note: ...does not necessarily outlive the anonymous lifetime defined here
+note: the anonymous lifetime defined here...
   --> $DIR/issue-27942.rs:5:15
    |
 LL |     fn select(&self) -> BufferViewHandle<R>;
    |               ^^^^^
+note: ...does not necessarily outlive the lifetime `'a` as defined here
+  --> $DIR/issue-27942.rs:3:18
+   |
+LL | pub trait Buffer<'a, R: Resources<'a>> {
+   |                  ^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/issues/issue-87199.rs b/tests/ui/issues/issue-87199.rs
index 081c45d6151..34879c5a7ca 100644
--- a/tests/ui/issues/issue-87199.rs
+++ b/tests/ui/issues/issue-87199.rs
@@ -11,6 +11,7 @@ fn ref_arg<T: ?Send>(_: &T) {}
 //~^ warning: relaxing a default bound only does something for `?Sized`
 fn ret() -> impl Iterator<Item = ()> + ?Send { std::iter::empty() }
 //~^ warning: relaxing a default bound only does something for `?Sized`
+//~| warning: relaxing a default bound only does something for `?Sized`
 
 // Check that there's no `?Sized` relaxation!
 fn main() {
diff --git a/tests/ui/issues/issue-87199.stderr b/tests/ui/issues/issue-87199.stderr
index 34433eef5c7..a0ed2946fb4 100644
--- a/tests/ui/issues/issue-87199.stderr
+++ b/tests/ui/issues/issue-87199.stderr
@@ -16,8 +16,16 @@ warning: relaxing a default bound only does something for `?Sized`; all other tr
 LL | fn ret() -> impl Iterator<Item = ()> + ?Send { std::iter::empty() }
    |                                        ^^^^^
 
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
+  --> $DIR/issue-87199.rs:12:40
+   |
+LL | fn ret() -> impl Iterator<Item = ()> + ?Send { std::iter::empty() }
+   |                                        ^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
-  --> $DIR/issue-87199.rs:18:15
+  --> $DIR/issue-87199.rs:19:15
    |
 LL |     ref_arg::<[i32]>(&[5]);
    |               ^^^^^ doesn't have a size known at compile-time
@@ -33,6 +41,6 @@ help: consider relaxing the implicit `Sized` restriction
 LL | fn ref_arg<T: ?Send + ?Sized>(_: &T) {}
    |                     ++++++++
 
-error: aborting due to 1 previous error; 3 warnings emitted
+error: aborting due to 1 previous error; 4 warnings emitted
 
 For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/lifetimes/could-not-resolve-issue-121503.rs b/tests/ui/lifetimes/could-not-resolve-issue-121503.rs
index 6bc70a907d9..363162370f2 100644
--- a/tests/ui/lifetimes/could-not-resolve-issue-121503.rs
+++ b/tests/ui/lifetimes/could-not-resolve-issue-121503.rs
@@ -4,8 +4,7 @@
 struct Struct;
 impl Struct {
     async fn box_ref_Struct(self: Box<Self, impl FnMut(&mut Self)>) -> &u32 {
-    //~^ ERROR the trait bound `impl FnMut(&mut Self): Allocator` is not satisfied
-    //~| ERROR Box<Struct, impl FnMut(&mut Self)>` cannot be used as the type of `self` without
+    //~^ ERROR Box<Struct, impl FnMut(&mut Self)>` cannot be used as the type of `self` without
         &1
     }
 }
diff --git a/tests/ui/lifetimes/could-not-resolve-issue-121503.stderr b/tests/ui/lifetimes/could-not-resolve-issue-121503.stderr
index a5d8239a2df..3babf63347c 100644
--- a/tests/ui/lifetimes/could-not-resolve-issue-121503.stderr
+++ b/tests/ui/lifetimes/could-not-resolve-issue-121503.stderr
@@ -1,16 +1,3 @@
-error[E0277]: the trait bound `impl FnMut(&mut Self): Allocator` is not satisfied
-  --> $DIR/could-not-resolve-issue-121503.rs:6:5
-   |
-LL |     async fn box_ref_Struct(self: Box<Self, impl FnMut(&mut Self)>) -> &u32 {
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Allocator` is not implemented for `impl FnMut(&mut Self)`
-   |
-note: required by a bound in `Box`
-  --> $SRC_DIR/alloc/src/boxed.rs:LL:COL
-help: consider further restricting this bound
-   |
-LL |     async fn box_ref_Struct(self: Box<Self, impl FnMut(&mut Self) + std::alloc::Allocator>) -> &u32 {
-   |                                                                   +++++++++++++++++++++++
-
 error[E0658]: `Box<Struct, impl FnMut(&mut Self)>` cannot be used as the type of `self` without the `arbitrary_self_types` feature
   --> $DIR/could-not-resolve-issue-121503.rs:6:35
    |
@@ -22,7 +9,6 @@ LL |     async fn box_ref_Struct(self: Box<Self, impl FnMut(&mut Self)>) -> &u32
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
    = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
 
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0277, E0658.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/tests/ui/lifetimes/issue-26638.rs b/tests/ui/lifetimes/issue-26638.rs
index 4bec3b3415b..11c730165f2 100644
--- a/tests/ui/lifetimes/issue-26638.rs
+++ b/tests/ui/lifetimes/issue-26638.rs
@@ -1,6 +1,5 @@
 fn parse_type(iter: Box<dyn Iterator<Item=&str>+'static>) -> &str { iter.next() }
 //~^ ERROR missing lifetime specifier [E0106]
-//~| ERROR mismatched types
 
 fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
 //~^ ERROR missing lifetime specifier [E0106]
diff --git a/tests/ui/lifetimes/issue-26638.stderr b/tests/ui/lifetimes/issue-26638.stderr
index ee958686259..403a8c67ccb 100644
--- a/tests/ui/lifetimes/issue-26638.stderr
+++ b/tests/ui/lifetimes/issue-26638.stderr
@@ -11,7 +11,7 @@ LL | fn parse_type<'a>(iter: Box<dyn Iterator<Item=&'a str>+'static>) -> &'a str
    |              ++++                              ++                    ++
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/issue-26638.rs:5:40
+  --> $DIR/issue-26638.rs:4:40
    |
 LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
    |                                        ^ expected named lifetime parameter
@@ -31,7 +31,7 @@ LL | fn parse_type_2(iter: fn(&u8)->&u8) -> String { iter() }
    |                                        ~~~~~~
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/issue-26638.rs:10:22
+  --> $DIR/issue-26638.rs:9:22
    |
 LL | fn parse_type_3() -> &str { unimplemented!() }
    |                      ^ expected named lifetime parameter
@@ -46,23 +46,8 @@ help: instead, you are more likely to want to return an owned value
 LL | fn parse_type_3() -> String { unimplemented!() }
    |                      ~~~~~~
 
-error[E0308]: mismatched types
-  --> $DIR/issue-26638.rs:1:69
-   |
-LL | fn parse_type(iter: Box<dyn Iterator<Item=&str>+'static>) -> &str { iter.next() }
-   |                                                              ----   ^^^^^^^^^^^ expected `&str`, found `Option<&str>`
-   |                                                              |
-   |                                                              expected `&str` because of return type
-   |
-   = note: expected reference `&str`
-                   found enum `Option<&str>`
-help: consider using `Option::expect` to unwrap the `Option<&str>` value, panicking if the value is an `Option::None`
-   |
-LL | fn parse_type(iter: Box<dyn Iterator<Item=&str>+'static>) -> &str { iter.next().expect("REASON") }
-   |                                                                                +++++++++++++++++
-
 error[E0061]: this function takes 1 argument but 0 arguments were supplied
-  --> $DIR/issue-26638.rs:5:47
+  --> $DIR/issue-26638.rs:4:47
    |
 LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
    |                                               ^^^^-- an argument of type `&u8` is missing
@@ -73,7 +58,7 @@ LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter(/* &u8 */) }
    |                                                   ~~~~~~~~~~~
 
 error[E0308]: mismatched types
-  --> $DIR/issue-26638.rs:5:47
+  --> $DIR/issue-26638.rs:4:47
    |
 LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
    |                                        ----   ^^^^^^ expected `&str`, found `&u8`
@@ -83,7 +68,7 @@ LL | fn parse_type_2(iter: fn(&u8)->&u8) -> &str { iter() }
    = note: expected reference `&'static str`
               found reference `&u8`
 
-error: aborting due to 6 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0061, E0106, E0308.
 For more information about an error, try `rustc --explain E0061`.
diff --git a/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.rs b/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.rs
index 56f89b70410..d6c918843c7 100644
--- a/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.rs
+++ b/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.rs
@@ -1,7 +1,5 @@
 fn foo(x: &i32, y: &i32) -> &i32 { //~ ERROR missing lifetime
     if x > y { x } else { y }
-    //~^ ERROR: lifetime may not live long enough
-    //~| ERROR: lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.stderr b/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.stderr
index db5b039d1c2..62b0a8a04bf 100644
--- a/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.stderr
+++ b/tests/ui/lifetimes/lifetime-errors/ex1b-return-no-names-if-else.stderr
@@ -10,22 +10,6 @@ help: consider introducing a named lifetime parameter
 LL | fn foo<'a>(x: &'a i32, y: &'a i32) -> &'a i32 {
    |       ++++     ++          ++          ++
 
-error: lifetime may not live long enough
-  --> $DIR/ex1b-return-no-names-if-else.rs:2:16
-   |
-LL | fn foo(x: &i32, y: &i32) -> &i32 {
-   |           - let's call the lifetime of this reference `'1`
-LL |     if x > y { x } else { y }
-   |                ^ returning this value requires that `'1` must outlive `'static`
-
-error: lifetime may not live long enough
-  --> $DIR/ex1b-return-no-names-if-else.rs:2:27
-   |
-LL | fn foo(x: &i32, y: &i32) -> &i32 {
-   |                    - let's call the lifetime of this reference `'2`
-LL |     if x > y { x } else { y }
-   |                           ^ returning this value requires that `'2` must outlive `'static`
-
-error: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0106`.
diff --git a/tests/ui/lint/lint-qualification.fixed b/tests/ui/lint/lint-qualification.fixed
index 2070bbcef52..7c8fd5236e6 100644
--- a/tests/ui/lint/lint-qualification.fixed
+++ b/tests/ui/lint/lint-qualification.fixed
@@ -35,6 +35,7 @@ fn main() {
         foo::bar();
         foo::$b(); // issue #96698
         $a::bar();
+        $a::$b();
     } }
     m!(foo, bar);
 }
diff --git a/tests/ui/lint/lint-qualification.rs b/tests/ui/lint/lint-qualification.rs
index 41b7e17c6ed..009b3080d5c 100644
--- a/tests/ui/lint/lint-qualification.rs
+++ b/tests/ui/lint/lint-qualification.rs
@@ -35,6 +35,7 @@ fn main() {
         foo::bar();
         foo::$b(); // issue #96698
         $a::bar();
+        $a::$b();
     } }
     m!(foo, bar);
 }
diff --git a/tests/ui/lint/unused/unused-associated-item.rs b/tests/ui/lint/unused/unused-associated-item.rs
new file mode 100644
index 00000000000..27cb4e979f1
--- /dev/null
+++ b/tests/ui/lint/unused/unused-associated-item.rs
@@ -0,0 +1,21 @@
+//@ check-pass
+
+#![deny(unused_must_use)]
+
+use std::future::Future;
+use std::pin::Pin;
+
+trait Factory {
+    type Output;
+}
+
+impl Factory for () {
+    type Output = Pin<Box<dyn Future<Output = ()> + 'static>>;
+}
+
+// Make sure we don't get an `unused_must_use` error on the *associated type bound*.
+fn f() -> impl Factory<Output: Future> {}
+
+fn main() {
+    f();
+}
diff --git a/tests/ui/match/postfix-match/pf-match-chain.rs b/tests/ui/match/postfix-match/pf-match-chain.rs
new file mode 100644
index 00000000000..80546e1963b
--- /dev/null
+++ b/tests/ui/match/postfix-match/pf-match-chain.rs
@@ -0,0 +1,16 @@
+//@ run-pass
+
+#![feature(postfix_match)]
+
+fn main() {
+    1.match {
+        2 => Some(0),
+        _ => None,
+    }.match {
+        None => Ok(true),
+        Some(_) => Err("nope")
+    }.match {
+        Ok(_) => (),
+        Err(_) => panic!()
+    }
+}
diff --git a/tests/ui/match/postfix-match/pf-match-exhaustiveness.rs b/tests/ui/match/postfix-match/pf-match-exhaustiveness.rs
new file mode 100644
index 00000000000..f4cac46f7cd
--- /dev/null
+++ b/tests/ui/match/postfix-match/pf-match-exhaustiveness.rs
@@ -0,0 +1,7 @@
+#![feature(postfix_match)]
+
+fn main() {
+    Some(1).match { //~ non-exhaustive patterns
+        None => {},
+    }
+}
diff --git a/tests/ui/match/postfix-match/pf-match-exhaustiveness.stderr b/tests/ui/match/postfix-match/pf-match-exhaustiveness.stderr
new file mode 100644
index 00000000000..f458218bb5d
--- /dev/null
+++ b/tests/ui/match/postfix-match/pf-match-exhaustiveness.stderr
@@ -0,0 +1,21 @@
+error[E0004]: non-exhaustive patterns: `Some(_)` not covered
+  --> $DIR/pf-match-exhaustiveness.rs:4:5
+   |
+LL |     Some(1).match {
+   |     ^^^^^^^ pattern `Some(_)` not covered
+   |
+note: `Option<i32>` defined here
+  --> $SRC_DIR/core/src/option.rs:LL:COL
+  ::: $SRC_DIR/core/src/option.rs:LL:COL
+   |
+   = note: not covered
+   = note: the matched value is of type `Option<i32>`
+help: ensure that all possible cases are being handled by adding a match arm with a wildcard pattern or an explicit pattern as shown
+   |
+LL ~         None => {},
+LL ~         Some(_) => todo!(),
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0004`.
diff --git a/tests/ui/match/postfix-match/pf-match-types.rs b/tests/ui/match/postfix-match/pf-match-types.rs
new file mode 100644
index 00000000000..af205926fb6
--- /dev/null
+++ b/tests/ui/match/postfix-match/pf-match-types.rs
@@ -0,0 +1,15 @@
+#![feature(postfix_match)]
+
+fn main() {
+    Some(10).match {
+    //~^ NOTE `match` arms have incompatible types
+        Some(5) => false,
+        //~^ NOTE this is found to be of type `bool`
+        Some(2) => true,
+        //~^ NOTE this is found to be of type `bool`
+        None    => (),
+        //~^ ERROR `match` arms have incompatible types
+        //~| NOTE expected `bool`, found `()`
+        _       => true
+    }
+}
diff --git a/tests/ui/match/postfix-match/pf-match-types.stderr b/tests/ui/match/postfix-match/pf-match-types.stderr
new file mode 100644
index 00000000000..0cfc1363d5f
--- /dev/null
+++ b/tests/ui/match/postfix-match/pf-match-types.stderr
@@ -0,0 +1,21 @@
+error[E0308]: `match` arms have incompatible types
+  --> $DIR/pf-match-types.rs:10:20
+   |
+LL | /     Some(10).match {
+LL | |
+LL | |         Some(5) => false,
+   | |                    ----- this is found to be of type `bool`
+LL | |
+LL | |         Some(2) => true,
+   | |                    ---- this is found to be of type `bool`
+LL | |
+LL | |         None    => (),
+   | |                    ^^ expected `bool`, found `()`
+...  |
+LL | |         _       => true
+LL | |     }
+   | |_____- `match` arms have incompatible types
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/match/postfix-match/postfix-match.rs b/tests/ui/match/postfix-match/postfix-match.rs
new file mode 100644
index 00000000000..03c4e8ab545
--- /dev/null
+++ b/tests/ui/match/postfix-match/postfix-match.rs
@@ -0,0 +1,62 @@
+//@ run-pass
+
+#![feature(postfix_match)]
+
+struct Bar {
+    foo: u8,
+    baz: u8,
+}
+
+pub fn main() {
+    let thing = Some("thing");
+
+    thing.match {
+        Some("nothing") => {},
+        Some(text) if text.eq_ignore_ascii_case("tapir")  => {},
+        Some("true") | Some("false") => {},
+        Some("thing") => {},
+        Some(_) => {},
+        None => {}
+    };
+
+    let num = 2u8;
+
+    num.match {
+        0 => {},
+        1..=5 => {},
+        _ => {},
+    };
+
+    let slic = &[1, 2, 3, 4][..];
+
+    slic.match {
+        [1] => {},
+        [2, _tail @ ..] => {},
+        [1, _] => {},
+        _ => {},
+    };
+
+    slic[0].match {
+        1 => 0,
+        i => i,
+    };
+
+    let out = (1, 2).match {
+        (1, 3) => 0,
+        (_, 1) => 0,
+        (1, i) => i,
+        _ => 3,
+    };
+    assert!(out == 2);
+
+    let strct = Bar {
+        foo: 3,
+        baz: 4
+    };
+
+    strct.match {
+        Bar { foo: 1, .. } => {},
+        Bar { baz: 2, .. } => {},
+        _ => (),
+    };
+}
diff --git a/tests/ui/nll/issue-54189.rs b/tests/ui/nll/issue-54189.rs
index 70aecc384ef..2339a722a7b 100644
--- a/tests/ui/nll/issue-54189.rs
+++ b/tests/ui/nll/issue-54189.rs
@@ -1,5 +1,6 @@
 fn bug() -> impl for <'r> Fn() -> &'r () { || { &() } }
 //~^ ERROR binding for associated type `Output` references lifetime `'r`
+//~| ERROR binding for associated type `Output` references lifetime `'r`
 
 fn main() {
     let f = bug();
diff --git a/tests/ui/nll/issue-54189.stderr b/tests/ui/nll/issue-54189.stderr
index 14ed2bb222d..ce756a91f56 100644
--- a/tests/ui/nll/issue-54189.stderr
+++ b/tests/ui/nll/issue-54189.stderr
@@ -4,6 +4,14 @@ error[E0582]: binding for associated type `Output` references lifetime `'r`, whi
 LL | fn bug() -> impl for <'r> Fn() -> &'r () { || { &() } }
    |                                   ^^^^^^
 
-error: aborting due to 1 previous error
+error[E0582]: binding for associated type `Output` references lifetime `'r`, which does not appear in the trait input types
+  --> $DIR/issue-54189.rs:1:35
+   |
+LL | fn bug() -> impl for <'r> Fn() -> &'r () { || { &() } }
+   |                                   ^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0582`.
diff --git a/tests/ui/nll/user-annotations/region-error-ice-109072.rs b/tests/ui/nll/user-annotations/region-error-ice-109072.rs
index 3f2ad3ccbf5..bcdc6651cf5 100644
--- a/tests/ui/nll/user-annotations/region-error-ice-109072.rs
+++ b/tests/ui/nll/user-annotations/region-error-ice-109072.rs
@@ -11,4 +11,5 @@ impl Lt<'missing> for () { //~ ERROR undeclared lifetime
 
 fn main() {
     let _: <() as Lt<'_>>::T = &();
+    //~^ ERROR the trait bound `(): Lt<'_>` is not satisfied
 }
diff --git a/tests/ui/nll/user-annotations/region-error-ice-109072.stderr b/tests/ui/nll/user-annotations/region-error-ice-109072.stderr
index d90971bed25..c187c17d98c 100644
--- a/tests/ui/nll/user-annotations/region-error-ice-109072.stderr
+++ b/tests/ui/nll/user-annotations/region-error-ice-109072.stderr
@@ -21,6 +21,13 @@ help: consider introducing lifetime `'missing` here
 LL | impl<'missing> Lt<'missing> for () {
    |     ++++++++++
 
-error: aborting due to 2 previous errors
+error[E0277]: the trait bound `(): Lt<'_>` is not satisfied
+  --> $DIR/region-error-ice-109072.rs:13:13
+   |
+LL |     let _: <() as Lt<'_>>::T = &();
+   |             ^^ the trait `Lt<'_>` is not implemented for `()`
+
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0261`.
+Some errors have detailed explanations: E0261, E0277.
+For more information about an error, try `rustc --explain E0261`.
diff --git a/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.rs b/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.rs
index 345c8a25f79..51be999a632 100644
--- a/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.rs
+++ b/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.rs
@@ -15,7 +15,6 @@ fn is_static<T>(_: T) where T: 'static { }
 // code forces us into a conservative, hacky path.
 fn bar(x: &str) -> &dyn Foo<Item = dyn Bar> { &() }
 //~^ ERROR please supply an explicit bound
-//~| ERROR `(): Foo<'_>` is not satisfied
 
 fn main() {
     let s = format!("foo");
diff --git a/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.stderr b/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.stderr
index d227c8778fe..688f8af0822 100644
--- a/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.stderr
+++ b/tests/ui/object-lifetime/object-lifetime-default-dyn-binding-nonstatic3.stderr
@@ -4,20 +4,6 @@ error[E0228]: the lifetime bound for this object type cannot be deduced from con
 LL | fn bar(x: &str) -> &dyn Foo<Item = dyn Bar> { &() }
    |                                    ^^^^^^^
 
-error[E0277]: the trait bound `(): Foo<'_>` is not satisfied
-  --> $DIR/object-lifetime-default-dyn-binding-nonstatic3.rs:16:47
-   |
-LL | fn bar(x: &str) -> &dyn Foo<Item = dyn Bar> { &() }
-   |                                               ^^^ the trait `Foo<'_>` is not implemented for `()`
-   |
-help: this trait has no implementations, consider adding one
-  --> $DIR/object-lifetime-default-dyn-binding-nonstatic3.rs:4:1
-   |
-LL | trait Foo<'a> {
-   | ^^^^^^^^^^^^^
-   = note: required for the cast from `&()` to `&dyn Foo<'_, Item = dyn Bar>`
-
-error: aborting due to 2 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0228, E0277.
-For more information about an error, try `rustc --explain E0228`.
+For more information about this error, try `rustc --explain E0228`.
diff --git a/tests/ui/parser/attribute/attr-bad-meta-4.rs b/tests/ui/parser/attribute/attr-bad-meta-4.rs
new file mode 100644
index 00000000000..cedbd1d6686
--- /dev/null
+++ b/tests/ui/parser/attribute/attr-bad-meta-4.rs
@@ -0,0 +1,12 @@
+macro_rules! mac {
+    ($attr_item: meta) => {
+        #[cfg($attr_item)]
+        //~^ ERROR expected unsuffixed literal or identifier, found `an(arbitrary token stream)`
+        //~| ERROR expected unsuffixed literal or identifier, found `an(arbitrary token stream)`
+        struct S;
+    }
+}
+
+mac!(an(arbitrary token stream));
+
+fn main() {}
diff --git a/tests/ui/parser/attribute/attr-bad-meta-4.stderr b/tests/ui/parser/attribute/attr-bad-meta-4.stderr
new file mode 100644
index 00000000000..a543bcb692e
--- /dev/null
+++ b/tests/ui/parser/attribute/attr-bad-meta-4.stderr
@@ -0,0 +1,25 @@
+error: expected unsuffixed literal or identifier, found `an(arbitrary token stream)`
+  --> $DIR/attr-bad-meta-4.rs:3:15
+   |
+LL |         #[cfg($attr_item)]
+   |               ^^^^^^^^^^
+...
+LL | mac!(an(arbitrary token stream));
+   | -------------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `mac` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: expected unsuffixed literal or identifier, found `an(arbitrary token stream)`
+  --> $DIR/attr-bad-meta-4.rs:3:15
+   |
+LL |         #[cfg($attr_item)]
+   |               ^^^^^^^^^^
+...
+LL | mac!(an(arbitrary token stream));
+   | -------------------------------- in this macro invocation
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+   = note: this error originates in the macro `mac` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/pattern/deref-patterns/typeck.rs b/tests/ui/pattern/deref-patterns/typeck.rs
new file mode 100644
index 00000000000..ead6dcdbaf0
--- /dev/null
+++ b/tests/ui/pattern/deref-patterns/typeck.rs
@@ -0,0 +1,31 @@
+//@ check-pass
+#![feature(deref_patterns)]
+#![allow(incomplete_features)]
+
+use std::rc::Rc;
+
+fn main() {
+    let vec: Vec<u32> = Vec::new();
+    match vec {
+        deref!([..]) => {}
+        _ => {}
+    }
+    match Box::new(true) {
+        deref!(true) => {}
+        _ => {}
+    }
+    match &Box::new(true) {
+        deref!(true) => {}
+        _ => {}
+    }
+    match &Rc::new(0) {
+        deref!(1..) => {}
+        _ => {}
+    }
+    // FIXME(deref_patterns): fails to typecheck because `"foo"` has type &str but deref creates a
+    // place of type `str`.
+    // match "foo".to_string() {
+    //     box "foo" => {}
+    //     _ => {}
+    // }
+}
diff --git a/tests/ui/raw-ref-op/raw-ref-temp.stderr b/tests/ui/raw-ref-op/raw-ref-temp.stderr
index b9666162517..1f6d85e4a7e 100644
--- a/tests/ui/raw-ref-op/raw-ref-temp.stderr
+++ b/tests/ui/raw-ref-op/raw-ref-temp.stderr
@@ -75,24 +75,32 @@ error[E0745]: cannot take address of a temporary
    |
 LL |     let ref_ascribe = &raw const type_ascribe!(2, i32);
    |                                  ^^^^^^^^^^^^^^^^^^^^^ temporary value
+   |
+   = note: this error originates in the macro `type_ascribe` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0745]: cannot take address of a temporary
   --> $DIR/raw-ref-temp.rs:27:36
    |
 LL |     let mut_ref_ascribe = &raw mut type_ascribe!(3, i32);
    |                                    ^^^^^^^^^^^^^^^^^^^^^ temporary value
+   |
+   = note: this error originates in the macro `type_ascribe` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0745]: cannot take address of a temporary
   --> $DIR/raw-ref-temp.rs:29:40
    |
 LL |     let ascribe_field_ref = &raw const type_ascribe!(PAIR.0, i32);
    |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^ temporary value
+   |
+   = note: this error originates in the macro `type_ascribe` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error[E0745]: cannot take address of a temporary
   --> $DIR/raw-ref-temp.rs:30:38
    |
 LL |     let ascribe_index_ref = &raw mut type_ascribe!(ARRAY[0], i32);
    |                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ temporary value
+   |
+   = note: this error originates in the macro `type_ascribe` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 16 previous errors
 
diff --git a/tests/ui/reachable/expr_type.stderr b/tests/ui/reachable/expr_type.stderr
index 70536326fd8..008b867e230 100644
--- a/tests/ui/reachable/expr_type.stderr
+++ b/tests/ui/reachable/expr_type.stderr
@@ -12,6 +12,7 @@ note: the lint level is defined here
    |
 LL | #![deny(unreachable_code)]
    |         ^^^^^^^^^^^^^^^^
+   = note: this error originates in the macro `type_ascribe` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-parse-not-item.stderr b/tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-parse-not-item.stderr
index ace2e7e46c4..12cc79f5961 100644
--- a/tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-parse-not-item.stderr
+++ b/tests/ui/rfcs/rfc-2632-const-trait-impl/const-closure-parse-not-item.stderr
@@ -4,5 +4,13 @@ error: `~const` can only be applied to `#[const_trait]` traits
 LL | const fn test() -> impl ~const Fn() {
    |                                ^^^^
 
-error: aborting due to 1 previous error
+error: `~const` can only be applied to `#[const_trait]` traits
+  --> $DIR/const-closure-parse-not-item.rs:7:32
+   |
+LL | const fn test() -> impl ~const Fn() {
+   |                                ^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 2 previous errors
 
diff --git a/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.rs b/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.rs
index 7d817d09c7f..21197fcaa27 100644
--- a/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.rs
+++ b/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.rs
@@ -1,7 +1,9 @@
 #![feature(const_trait_impl, effects)]
 
-const fn test() -> impl ~const Fn() { //~ ERROR `~const` can only be applied to `#[const_trait]` traits
-    //~^ ERROR cycle detected
+const fn test() -> impl ~const Fn() {
+    //~^ ERROR `~const` can only be applied to `#[const_trait]` traits
+    //~| ERROR `~const` can only be applied to `#[const_trait]` traits
+    //~| ERROR cycle detected
     const move || { //~ ERROR const closures are experimental
         let sl: &[u8] = b"foo";
 
diff --git a/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.stderr b/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.stderr
index 0f6240cc03b..2f805110917 100644
--- a/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.stderr
+++ b/tests/ui/rfcs/rfc-2632-const-trait-impl/effects/ice-112822-expected-type-for-param.stderr
@@ -1,5 +1,5 @@
 error[E0658]: const closures are experimental
-  --> $DIR/ice-112822-expected-type-for-param.rs:5:5
+  --> $DIR/ice-112822-expected-type-for-param.rs:7:5
    |
 LL |     const move || {
    |     ^^^^^
@@ -14,8 +14,16 @@ error: `~const` can only be applied to `#[const_trait]` traits
 LL | const fn test() -> impl ~const Fn() {
    |                                ^^^^
 
+error: `~const` can only be applied to `#[const_trait]` traits
+  --> $DIR/ice-112822-expected-type-for-param.rs:3:32
+   |
+LL | const fn test() -> impl ~const Fn() {
+   |                                ^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error[E0277]: can't compare `&u8` with `&u8`
-  --> $DIR/ice-112822-expected-type-for-param.rs:10:17
+  --> $DIR/ice-112822-expected-type-for-param.rs:12:17
    |
 LL |                 assert_eq!(first, &b'f');
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `&u8 == &u8`
@@ -54,7 +62,7 @@ LL | const fn test() -> impl ~const Fn() {
    |                    ^^^^^^^^^^^^^^^^
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
-error: aborting due to 4 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0277, E0391, E0658.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs b/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs
new file mode 100644
index 00000000000..a46a3afd734
--- /dev/null
+++ b/tests/ui/sanitizer/cfi-closure-fn-ptr-cast.rs
@@ -0,0 +1,18 @@
+// Tests that converting a closure to a function pointer works
+// The notable thing being tested here is that when the closure does not capture anything,
+// the call method from its Fn trait takes a ZST representing its environment. The compiler then
+// uses the assumption that the ZST is non-passed to reify this into a function pointer.
+//
+// This checks that the reified function pointer will have the expected alias set at its call-site.
+
+//@ needs-sanitizer-cfi
+// FIXME(#122848) Remove only-linux once OSX CFI binaries work
+//@ only-linux
+//@ compile-flags: --crate-type=bin -Cprefer-dynamic=off -Clto -Zsanitizer=cfi
+//@ compile-flags: -C target-feature=-crt-static -C codegen-units=1 -C opt-level=0
+//@ run-pass
+
+pub fn main() {
+    let f: &fn() = &((|| ()) as _);
+    f();
+}
diff --git a/tests/ui/stable-mir-print/basic_function.rs b/tests/ui/stable-mir-print/basic_function.rs
index 9b27a56dab1..deefef63bdb 100644
--- a/tests/ui/stable-mir-print/basic_function.rs
+++ b/tests/ui/stable-mir-print/basic_function.rs
@@ -2,7 +2,7 @@
 //@ check-pass
 //@ only-x86_64
 
-fn foo(i:i32) -> i32 {
+fn foo(i: i32) -> i32 {
     i + 1
 }
 
@@ -12,4 +12,13 @@ fn bar(vec: &mut Vec<i32>) -> Vec<i32> {
     new_vec
 }
 
-fn main(){}
+pub fn demux(input: u8) -> u8 {
+    match input {
+        0 => 10,
+        1 => 6,
+        2 => 8,
+        _ => 0,
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/stable-mir-print/basic_function.stdout b/tests/ui/stable-mir-print/basic_function.stdout
index d9b33a4257c..3926c1048f5 100644
--- a/tests/ui/stable-mir-print/basic_function.stdout
+++ b/tests/ui/stable-mir-print/basic_function.stdout
@@ -1,234 +1,74 @@
 // WARNING: This is highly experimental output it's intended for stable-mir developers only.
 // If you find a bug or want to improve the output open a issue at https://github.com/rust-lang/project-stable-mir.
-fn foo(_0: i32) -> i32 {
-    let mut _0: (i32, bool);
+fn foo(_1: i32) -> i32 {
+    let mut _0: i32;
+    let mut _2: (i32, bool);
+    debug i => _1;
+    bb0: {
+        _2 = CheckedAdd(_1, 1_i32);
+        assert(!move (_2.1: bool), "attempt to compute `{} + {}`, which would overflow", _1, 1_i32) -> [success: bb1, unwind continue];
+    }
+    bb1: {
+        _0 = move (_2.0: i32);
+        return;
+    }
 }
+fn bar(_1: &mut Vec<i32>) -> Vec<i32> {
+    let mut _0: Vec<i32>;
+    let mut _2: Vec<i32>;
+    let mut _3: &Vec<i32>;
+    let  _4: ();
+    let mut _5: &mut Vec<i32>;
+    debug vec => _1;
+    debug new_vec => _2;
     bb0: {
-        _2 = 1 Add const 1_i32
-        assert(!move _2 bool),"attempt to compute `{} + {}`, which would overflow", 1, const 1_i32) -> [success: bb1, unwind continue]
+        _3 = &(*_1);
+        _2 = <Vec<i32> as Clone>::clone(move _3) -> [return: bb1, unwind continue];
     }
     bb1: {
-        _0 = move _2
-        return
+        _5 = &mut _2;
+        _4 = Vec::<i32>::push(move _5, 1_i32) -> [return: bb2, unwind: bb3];
+    }
+    bb2: {
+        _0 = move _2;
+        return;
+    }
+    bb3: {
+        drop(_2) -> [return: bb4, unwind terminate];
+    }
+    bb4: {
+        resume;
     }
-fn bar(_0: &mut Ty {
-    id: 10,
-    kind: RigidTy(
-        Adt(
-            AdtDef(
-                DefId {
-                    id: 3,
-                    name: "std::vec::Vec",
-                },
-            ),
-            GenericArgs(
-                [
-                    Type(
-                        Ty {
-                            id: 11,
-                            kind: Param(
-                                ParamTy {
-                                    index: 0,
-                                    name: "T",
-                                },
-                            ),
-                        },
-                    ),
-                    Type(
-                        Ty {
-                            id: 12,
-                            kind: Param(
-                                ParamTy {
-                                    index: 1,
-                                    name: "A",
-                                },
-                            ),
-                        },
-                    ),
-                ],
-            ),
-        ),
-    ),
-}) -> Ty {
-    id: 10,
-    kind: RigidTy(
-        Adt(
-            AdtDef(
-                DefId {
-                    id: 3,
-                    name: "std::vec::Vec",
-                },
-            ),
-            GenericArgs(
-                [
-                    Type(
-                        Ty {
-                            id: 11,
-                            kind: Param(
-                                ParamTy {
-                                    index: 0,
-                                    name: "T",
-                                },
-                            ),
-                        },
-                    ),
-                    Type(
-                        Ty {
-                            id: 12,
-                            kind: Param(
-                                ParamTy {
-                                    index: 1,
-                                    name: "A",
-                                },
-                            ),
-                        },
-                    ),
-                ],
-            ),
-        ),
-    ),
-} {
-    let mut _0: Ty {
-    id: 10,
-    kind: RigidTy(
-        Adt(
-            AdtDef(
-                DefId {
-                    id: 3,
-                    name: "std::vec::Vec",
-                },
-            ),
-            GenericArgs(
-                [
-                    Type(
-                        Ty {
-                            id: 11,
-                            kind: Param(
-                                ParamTy {
-                                    index: 0,
-                                    name: "T",
-                                },
-                            ),
-                        },
-                    ),
-                    Type(
-                        Ty {
-                            id: 12,
-                            kind: Param(
-                                ParamTy {
-                                    index: 1,
-                                    name: "A",
-                                },
-                            ),
-                        },
-                    ),
-                ],
-            ),
-        ),
-    ),
-};
-    let mut _1: &Ty {
-    id: 10,
-    kind: RigidTy(
-        Adt(
-            AdtDef(
-                DefId {
-                    id: 3,
-                    name: "std::vec::Vec",
-                },
-            ),
-            GenericArgs(
-                [
-                    Type(
-                        Ty {
-                            id: 11,
-                            kind: Param(
-                                ParamTy {
-                                    index: 0,
-                                    name: "T",
-                                },
-                            ),
-                        },
-                    ),
-                    Type(
-                        Ty {
-                            id: 12,
-                            kind: Param(
-                                ParamTy {
-                                    index: 1,
-                                    name: "A",
-                                },
-                            ),
-                        },
-                    ),
-                ],
-            ),
-        ),
-    ),
-};
-    let _2: ();
-    let mut _3: &mut Ty {
-    id: 10,
-    kind: RigidTy(
-        Adt(
-            AdtDef(
-                DefId {
-                    id: 3,
-                    name: "std::vec::Vec",
-                },
-            ),
-            GenericArgs(
-                [
-                    Type(
-                        Ty {
-                            id: 11,
-                            kind: Param(
-                                ParamTy {
-                                    index: 0,
-                                    name: "T",
-                                },
-                            ),
-                        },
-                    ),
-                    Type(
-                        Ty {
-                            id: 12,
-                            kind: Param(
-                                ParamTy {
-                                    index: 1,
-                                    name: "A",
-                                },
-                            ),
-                        },
-                    ),
-                ],
-            ),
-        ),
-    ),
-};
 }
+fn demux(_1: u8) -> u8 {
+    let mut _0: u8;
+    debug input => _1;
     bb0: {
-        _3 = refShared1
-        _2 = const <Vec<i32> as Clone>::clone(move _3) -> [return: bb1, unwind continue]
+        switchInt(_1) -> [0: bb2, 1: bb3, 2: bb4, otherwise: bb1];
     }
     bb1: {
-        _5 = refMut {
-    kind: TwoPhaseBorrow,
-}2
-        _4 = const Vec::<i32>::push(move _5, const 1_i32) -> [return: bb2, unwind: bb3]
+        _0 = 0_u8;
+        goto -> bb5;
     }
     bb2: {
-        _0 = move _2
-        return
+        _0 = 10_u8;
+        goto -> bb5;
     }
     bb3: {
-        drop(_2) -> [return: bb4, unwind terminate]
+        _0 = 6_u8;
+        goto -> bb5;
     }
     bb4: {
-        resume
+        _0 = 8_u8;
+        goto -> bb5;
+    }
+    bb5: {
+        return;
     }
-fn main() -> () {
 }
+fn main() -> () {
+    let mut _0: ();
     bb0: {
-        return
+        return;
     }
+}
diff --git a/tests/ui/suggestions/issue-85347.rs b/tests/ui/suggestions/issue-85347.rs
index 04d4c47d8e5..d14cf07d915 100644
--- a/tests/ui/suggestions/issue-85347.rs
+++ b/tests/ui/suggestions/issue-85347.rs
@@ -4,6 +4,9 @@ trait Foo {
     //~^ ERROR associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
     //~| ERROR associated type bindings are not allowed here
     //~| HELP add missing
+    //~| ERROR associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
+    //~| ERROR associated type bindings are not allowed here
+    //~| HELP add missing
 }
 
 fn main() {}
diff --git a/tests/ui/suggestions/issue-85347.stderr b/tests/ui/suggestions/issue-85347.stderr
index f330b3c1fad..45f87e539b4 100644
--- a/tests/ui/suggestions/issue-85347.stderr
+++ b/tests/ui/suggestions/issue-85347.stderr
@@ -20,7 +20,32 @@ error[E0229]: associated type bindings are not allowed here
 LL |     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
    |                                              ^^^^^^^^^^^^^ associated type not allowed here
 
-error: aborting due to 2 previous errors
+error[E0107]: associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
+  --> $DIR/issue-85347.rs:3:42
+   |
+LL |     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
+   |                                          ^^^ expected 1 lifetime argument
+   |
+note: associated type defined here, with 1 lifetime parameter: `'a`
+  --> $DIR/issue-85347.rs:3:10
+   |
+LL |     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
+   |          ^^^ --
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: add missing lifetime argument
+   |
+LL |     type Bar<'a>: Deref<Target = <Self>::Bar<'a, Target = Self>>;
+   |                                              +++
+
+error[E0229]: associated type bindings are not allowed here
+  --> $DIR/issue-85347.rs:3:46
+   |
+LL |     type Bar<'a>: Deref<Target = <Self>::Bar<Target = Self>>;
+   |                                              ^^^^^^^^^^^^^ associated type not allowed here
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 4 previous errors
 
 Some errors have detailed explanations: E0107, E0229.
 For more information about an error, try `rustc --explain E0107`.
diff --git a/tests/ui/suggestions/issue-86667.rs b/tests/ui/suggestions/issue-86667.rs
index 8c18a879238..1f37e9a5f6d 100644
--- a/tests/ui/suggestions/issue-86667.rs
+++ b/tests/ui/suggestions/issue-86667.rs
@@ -6,13 +6,11 @@
 async fn a(s1: &str, s2: &str) -> &str {
     //~^ ERROR: missing lifetime specifier [E0106]
     s1
-    //~^ ERROR: lifetime may not live long enough
 }
 
 fn b(s1: &str, s2: &str) -> &str {
     //~^ ERROR: missing lifetime specifier [E0106]
     s1
-    //~^ ERROR lifetime may not live long enough
 }
 
 fn main() {}
diff --git a/tests/ui/suggestions/issue-86667.stderr b/tests/ui/suggestions/issue-86667.stderr
index e3d673ff233..14dbbfffb0e 100644
--- a/tests/ui/suggestions/issue-86667.stderr
+++ b/tests/ui/suggestions/issue-86667.stderr
@@ -11,7 +11,7 @@ LL | async fn a<'a>(s1: &'a str, s2: &'a str) -> &'a str {
    |           ++++      ++           ++          ++
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/issue-86667.rs:12:29
+  --> $DIR/issue-86667.rs:11:29
    |
 LL | fn b(s1: &str, s2: &str) -> &str {
    |          ----      ----     ^ expected named lifetime parameter
@@ -22,24 +22,6 @@ help: consider introducing a named lifetime parameter
 LL | fn b<'a>(s1: &'a str, s2: &'a str) -> &'a str {
    |     ++++      ++           ++          ++
 
-error: lifetime may not live long enough
-  --> $DIR/issue-86667.rs:8:5
-   |
-LL | async fn a(s1: &str, s2: &str) -> &str {
-   |                - let's call the lifetime of this reference `'1`
-LL |
-LL |     s1
-   |     ^^ returning this value requires that `'1` must outlive `'static`
-
-error: lifetime may not live long enough
-  --> $DIR/issue-86667.rs:14:5
-   |
-LL | fn b(s1: &str, s2: &str) -> &str {
-   |          - let's call the lifetime of this reference `'1`
-LL |
-LL |     s1
-   |     ^^ returning this value requires that `'1` must outlive `'static`
-
-error: aborting due to 4 previous errors
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0106`.
diff --git a/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs b/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs
new file mode 100644
index 00000000000..34afd363129
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs
@@ -0,0 +1,12 @@
+fn main() {}
+
+fn foo(_src: &crate::Foo) -> Option<i32> {
+    todo!()
+}
+fn bar(src: &crate::Foo) -> impl Iterator<Item = i32> {
+    [0].into_iter()
+ //~^ ERROR hidden type for `impl Iterator<Item = i32>` captures lifetime that does not appear in bounds
+        .filter_map(|_| foo(src))
+}
+
+struct Foo<'a>(&'a str);
diff --git a/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr b/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr
new file mode 100644
index 00000000000..aeeec3aca34
--- /dev/null
+++ b/tests/ui/suggestions/lifetimes/explicit-lifetime-suggestion-in-proper-span-issue-121267.stderr
@@ -0,0 +1,20 @@
+error[E0700]: hidden type for `impl Iterator<Item = i32>` captures lifetime that does not appear in bounds
+  --> $DIR/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs:7:5
+   |
+LL |   fn bar(src: &crate::Foo) -> impl Iterator<Item = i32> {
+   |                ----------     ------------------------- opaque type defined here
+   |                |
+   |                hidden type `FilterMap<std::slice::Iter<'static, i32>, {closure@$DIR/explicit-lifetime-suggestion-in-proper-span-issue-121267.rs:9:21: 9:24}>` captures the anonymous lifetime defined here
+LL | /     [0].into_iter()
+LL | |
+LL | |         .filter_map(|_| foo(src))
+   | |_________________________________^
+   |
+help: to declare that `impl Iterator<Item = i32>` captures `'_`, you can introduce a named lifetime parameter `'a`
+   |
+LL | fn bar<'a>(src: &'a crate::Foo<'a>) -> impl Iterator<Item = i32> + 'a  {
+   |       ++++       ++           ++++                               ++++
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0700`.
diff --git a/tests/ui/suggestions/missing-lifetime-specifier.rs b/tests/ui/suggestions/missing-lifetime-specifier.rs
index 3fa7f75f862..cd7fa0c1d85 100644
--- a/tests/ui/suggestions/missing-lifetime-specifier.rs
+++ b/tests/ui/suggestions/missing-lifetime-specifier.rs
@@ -20,31 +20,21 @@ pub union Qux<'t, 'k, I> {
 trait Tar<'t, 'k, I> {}
 
 thread_local! {
-    //~^ ERROR lifetime may not live long enough
-    //~| ERROR lifetime may not live long enough
     static a: RefCell<HashMap<i32, Vec<Vec<Foo>>>> = RefCell::new(HashMap::new());
       //~^ ERROR missing lifetime specifiers
       //~| ERROR missing lifetime specifiers
 }
 thread_local! {
-    //~^ ERROR lifetime may not live long enough
-    //~| ERROR lifetime may not live long enough
-    //~| ERROR lifetime may not live long enough
     static b: RefCell<HashMap<i32, Vec<Vec<&Bar>>>> = RefCell::new(HashMap::new());
       //~^ ERROR missing lifetime specifiers
       //~| ERROR missing lifetime specifiers
 }
 thread_local! {
-    //~^ ERROR lifetime may not live long enough
-    //~| ERROR lifetime may not live long enough
     static c: RefCell<HashMap<i32, Vec<Vec<Qux<i32>>>>> = RefCell::new(HashMap::new());
     //~^ ERROR missing lifetime specifiers
     //~| ERROR missing lifetime specifiers
 }
 thread_local! {
-    //~^ ERROR lifetime may not live long enough
-    //~| ERROR lifetime may not live long enough
-    //~| ERROR lifetime may not live long enough
     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32>>>>> = RefCell::new(HashMap::new());
     //~^ ERROR missing lifetime specifiers
     //~| ERROR missing lifetime specifiers
diff --git a/tests/ui/suggestions/missing-lifetime-specifier.stderr b/tests/ui/suggestions/missing-lifetime-specifier.stderr
index 62eca162148..2b85cfde7b6 100644
--- a/tests/ui/suggestions/missing-lifetime-specifier.stderr
+++ b/tests/ui/suggestions/missing-lifetime-specifier.stderr
@@ -1,5 +1,5 @@
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:25:44
+  --> $DIR/missing-lifetime-specifier.rs:23:44
    |
 LL |     static a: RefCell<HashMap<i32, Vec<Vec<Foo>>>> = RefCell::new(HashMap::new());
    |                                            ^^^ expected 2 lifetime parameters
@@ -11,11 +11,9 @@ LL |     static a: RefCell<HashMap<i32, Vec<Vec<Foo<'static, 'static>>>>> = RefC
    |                                               ++++++++++++++++++
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:25:44
+  --> $DIR/missing-lifetime-specifier.rs:23:44
    |
 LL | / thread_local! {
-LL | |
-LL | |
 LL | |     static a: RefCell<HashMap<i32, Vec<Vec<Foo>>>> = RefCell::new(HashMap::new());
    | |                                            ^^^ expected 2 lifetime parameters
 LL | |
@@ -26,7 +24,7 @@ LL | | }
    = help: this function's return type contains a borrowed value, but the signature does not say which one of `init`'s 3 lifetimes it is borrowed from
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:33:44
+  --> $DIR/missing-lifetime-specifier.rs:28:44
    |
 LL |     static b: RefCell<HashMap<i32, Vec<Vec<&Bar>>>> = RefCell::new(HashMap::new());
    |                                            ^^^^ expected 2 lifetime parameters
@@ -40,12 +38,9 @@ LL |     static b: RefCell<HashMap<i32, Vec<Vec<&'static Bar<'static, 'static>>>
    |                                             +++++++    ++++++++++++++++++
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:33:44
+  --> $DIR/missing-lifetime-specifier.rs:28:44
    |
 LL | / thread_local! {
-LL | |
-LL | |
-LL | |
 LL | |     static b: RefCell<HashMap<i32, Vec<Vec<&Bar>>>> = RefCell::new(HashMap::new());
    | |                                            ^^^^ expected 2 lifetime parameters
    | |                                            |
@@ -58,7 +53,7 @@ LL | | }
    = help: this function's return type contains a borrowed value, but the signature does not say which one of `init`'s 4 lifetimes it is borrowed from
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:40:47
+  --> $DIR/missing-lifetime-specifier.rs:33:47
    |
 LL |     static c: RefCell<HashMap<i32, Vec<Vec<Qux<i32>>>>> = RefCell::new(HashMap::new());
    |                                               ^ expected 2 lifetime parameters
@@ -70,11 +65,9 @@ LL |     static c: RefCell<HashMap<i32, Vec<Vec<Qux<'static, 'static, i32>>>>> =
    |                                                +++++++++++++++++
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:40:47
+  --> $DIR/missing-lifetime-specifier.rs:33:47
    |
 LL | / thread_local! {
-LL | |
-LL | |
 LL | |     static c: RefCell<HashMap<i32, Vec<Vec<Qux<i32>>>>> = RefCell::new(HashMap::new());
    | |                                               ^ expected 2 lifetime parameters
 LL | |
@@ -85,7 +78,7 @@ LL | | }
    = help: this function's return type contains a borrowed value, but the signature does not say which one of `init`'s 3 lifetimes it is borrowed from
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:48:44
+  --> $DIR/missing-lifetime-specifier.rs:38:44
    |
 LL |     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32>>>>> = RefCell::new(HashMap::new());
    |                                            ^   ^ expected 2 lifetime parameters
@@ -99,12 +92,9 @@ LL |     static d: RefCell<HashMap<i32, Vec<Vec<&'static Tar<'static, 'static, i
    |                                             +++++++     +++++++++++++++++
 
 error[E0106]: missing lifetime specifiers
-  --> $DIR/missing-lifetime-specifier.rs:48:44
+  --> $DIR/missing-lifetime-specifier.rs:38:44
    |
 LL | / thread_local! {
-LL | |
-LL | |
-LL | |
 LL | |     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32>>>>> = RefCell::new(HashMap::new());
    | |                                            ^   ^ expected 2 lifetime parameters
    | |                                            |
@@ -117,7 +107,7 @@ LL | | }
    = help: this function's return type contains a borrowed value, but the signature does not say which one of `init`'s 4 lifetimes it is borrowed from
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/missing-lifetime-specifier.rs:58:44
+  --> $DIR/missing-lifetime-specifier.rs:48:44
    |
 LL |     static f: RefCell<HashMap<i32, Vec<Vec<&Tar<'static, i32>>>>> = RefCell::new(HashMap::new());
    |                                            ^ expected named lifetime parameter
@@ -129,7 +119,7 @@ LL |     static f: RefCell<HashMap<i32, Vec<Vec<&'static Tar<'static, i32>>>>> =
    |                                             +++++++
 
 error[E0106]: missing lifetime specifier
-  --> $DIR/missing-lifetime-specifier.rs:58:44
+  --> $DIR/missing-lifetime-specifier.rs:48:44
    |
 LL | / thread_local! {
 LL | |     static f: RefCell<HashMap<i32, Vec<Vec<&Tar<'static, i32>>>>> = RefCell::new(HashMap::new());
@@ -143,7 +133,7 @@ LL | | }
    = help: this function's return type contains a borrowed value, but the signature does not say which one of `init`'s 3 lifetimes it is borrowed from
 
 error[E0107]: union takes 2 lifetime arguments but 1 lifetime argument was supplied
-  --> $DIR/missing-lifetime-specifier.rs:54:44
+  --> $DIR/missing-lifetime-specifier.rs:44:44
    |
 LL |     static e: RefCell<HashMap<i32, Vec<Vec<Qux<'static, i32>>>>> = RefCell::new(HashMap::new());
    |                                            ^^^ ------- supplied 1 lifetime argument
@@ -161,7 +151,7 @@ LL |     static e: RefCell<HashMap<i32, Vec<Vec<Qux<'static, 'static, i32>>>>> =
    |                                                       +++++++++
 
 error[E0107]: trait takes 2 lifetime arguments but 1 lifetime argument was supplied
-  --> $DIR/missing-lifetime-specifier.rs:58:45
+  --> $DIR/missing-lifetime-specifier.rs:48:45
    |
 LL |     static f: RefCell<HashMap<i32, Vec<Vec<&Tar<'static, i32>>>>> = RefCell::new(HashMap::new());
    |                                             ^^^ ------- supplied 1 lifetime argument
@@ -178,199 +168,7 @@ help: add missing lifetime argument
 LL |     static f: RefCell<HashMap<i32, Vec<Vec<&Tar<'static, 'static, i32>>>>> = RefCell::new(HashMap::new());
    |                                                        +++++++++
 
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:22:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |     static a: RefCell<HashMap<i32, Vec<Vec<Foo>>>> = RefCell::new(HashMap::new());
-LL | |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<Foo<'1, '_>>>>>>>`
-   |   returning this value requires that `'1` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:22:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |     static a: RefCell<HashMap<i32, Vec<Vec<Foo>>>> = RefCell::new(HashMap::new());
-LL | |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<Foo<'_, '2>>>>>>>`
-   |   returning this value requires that `'2` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:29:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |
-LL | |     static b: RefCell<HashMap<i32, Vec<Vec<&Bar>>>> = RefCell::new(HashMap::new());
-   | |                                            - let's call the lifetime of this reference `'1`
-LL | |
-LL | |
-LL | | }
-   | |_^ returning this value requires that `'1` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: to declare that the trait object captures data from argument `init`, you can add an explicit `'_` lifetime bound
-   |
-LL |     static b: RefCell<HashMap<i32, Vec<Vec<&Bar + '_>>>> = RefCell::new(HashMap::new());
-   |                                                 ++++
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:29:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |
-...  |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<&dyn Bar<'2, '_>>>>>>>`
-   |   returning this value requires that `'2` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: to declare that the trait object captures data from argument `init`, you can add an explicit `'_` lifetime bound
-   |
-LL |     static b: RefCell<HashMap<i32, Vec<Vec<&Bar + '_>>>> = RefCell::new(HashMap::new());
-   |                                                 ++++
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:29:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |
-...  |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<&dyn Bar<'_, '3>>>>>>>`
-   |   returning this value requires that `'3` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: to declare that the trait object captures data from argument `init`, you can add an explicit `'_` lifetime bound
-   |
-LL |     static b: RefCell<HashMap<i32, Vec<Vec<&Bar + '_>>>> = RefCell::new(HashMap::new());
-   |                                                 ++++
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:37:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |     static c: RefCell<HashMap<i32, Vec<Vec<Qux<i32>>>>> = RefCell::new(HashMap::new());
-LL | |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<Qux<'1, '_, i32>>>>>>>`
-   |   returning this value requires that `'1` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:37:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |     static c: RefCell<HashMap<i32, Vec<Vec<Qux<i32>>>>> = RefCell::new(HashMap::new());
-LL | |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<Qux<'_, '2, i32>>>>>>>`
-   |   returning this value requires that `'2` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:44:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |
-LL | |     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32>>>>> = RefCell::new(HashMap::new());
-   | |                                            - let's call the lifetime of this reference `'1`
-LL | |
-LL | |
-LL | | }
-   | |_^ returning this value requires that `'1` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: to declare that the trait object captures data from argument `init`, you can add an explicit `'_` lifetime bound
-   |
-LL |     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32> + '_>>>> = RefCell::new(HashMap::new());
-   |                                                      ++++
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:44:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |
-...  |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<&dyn Tar<'2, '_, i32>>>>>>>`
-   |   returning this value requires that `'2` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: to declare that the trait object captures data from argument `init`, you can add an explicit `'_` lifetime bound
-   |
-LL |     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32> + '_>>>> = RefCell::new(HashMap::new());
-   |                                                      ++++
-
-error: lifetime may not live long enough
-  --> $DIR/missing-lifetime-specifier.rs:44:1
-   |
-LL | / thread_local! {
-LL | |
-LL | |
-LL | |
-...  |
-LL | |
-LL | | }
-   | | ^
-   | | |
-   | |_has type `Option<&mut Option<RefCell<HashMap<i32, Vec<Vec<&dyn Tar<'_, '3, i32>>>>>>>`
-   |   returning this value requires that `'3` must outlive `'static`
-   |
-   = note: this error originates in the macro `$crate::thread::local_impl::thread_local_inner` which comes from the expansion of the macro `thread_local` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: to declare that the trait object captures data from argument `init`, you can add an explicit `'_` lifetime bound
-   |
-LL |     static d: RefCell<HashMap<i32, Vec<Vec<&Tar<i32> + '_>>>> = RefCell::new(HashMap::new());
-   |                                                      ++++
-
-error: aborting due to 22 previous errors
+error: aborting due to 12 previous errors
 
 Some errors have detailed explanations: E0106, E0107.
 For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/suggestions/types/into-inference-needs-type.rs b/tests/ui/suggestions/types/into-inference-needs-type.rs
new file mode 100644
index 00000000000..4c8b6ec2113
--- /dev/null
+++ b/tests/ui/suggestions/types/into-inference-needs-type.rs
@@ -0,0 +1,15 @@
+#[derive(Debug)]
+enum MyError {
+    MainError
+}
+
+fn main() -> Result<(), MyError> {
+    let vec = vec!["one", "two", "three"];
+    let list = vec
+        .iter()
+        .map(|s| s.strip_prefix("t"))
+        .filter_map(Option::Some)
+        .into()?; //~ ERROR type annotations needed
+
+    return Ok(());
+}
diff --git a/tests/ui/suggestions/types/into-inference-needs-type.stderr b/tests/ui/suggestions/types/into-inference-needs-type.stderr
new file mode 100644
index 00000000000..dd688f90289
--- /dev/null
+++ b/tests/ui/suggestions/types/into-inference-needs-type.stderr
@@ -0,0 +1,19 @@
+error[E0283]: type annotations needed
+  --> $DIR/into-inference-needs-type.rs:12:10
+   |
+LL |         .into()?;
+   |          ^^^^
+   |
+   = note: cannot satisfy `_: From<FilterMap<Map<std::slice::Iter<'_, &str>, {closure@$DIR/into-inference-needs-type.rs:10:14: 10:17}>, fn(Option<&str>) -> Option<Option<&str>> {Option::<Option<&str>>::Some}>>`
+   = note: required for `FilterMap<Map<std::slice::Iter<'_, &str>, {closure@$DIR/into-inference-needs-type.rs:10:14: 10:17}>, fn(Option<&str>) -> Option<Option<&str>> {Option::<Option<&str>>::Some}>` to implement `Into<_>`
+help: try using a fully qualified path to specify the expected types
+   |
+LL ~     let list = <FilterMap<Map<std::slice::Iter<'_, &str>, _>, _> as Into<T>>::into(vec
+LL |         .iter()
+LL |         .map(|s| s.strip_prefix("t"))
+LL ~         .filter_map(Option::Some))?;
+   |
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0283`.
diff --git a/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.rs b/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.rs
index 7d71fcdd158..cab484a120c 100644
--- a/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.rs
+++ b/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.rs
@@ -20,6 +20,7 @@ impl<T, S> Trait<T, S> for () {}
 fn func<T: Trait<u32, String>>(t: T) -> impl Trait<(), i32> {
 //~^ ERROR trait takes 1 generic argument but 2 generic arguments were supplied
 //~| ERROR trait takes 1 generic argument but 2 generic arguments were supplied
+//~| ERROR trait takes 1 generic argument but 2 generic arguments were supplied
 //~| ERROR type annotations needed
     3
 }
diff --git a/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.stderr b/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.stderr
index f4ede4190fc..99e81a9039e 100644
--- a/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.stderr
+++ b/tests/ui/traits/associated_type_bound/116464-invalid-assoc-type-suggestion-in-trait-impl.stderr
@@ -54,6 +54,23 @@ help: replace the generic bound with the associated type
 LL | fn func<T: Trait<u32, String>>(t: T) -> impl Trait<(), Assoc = i32> {
    |                                                        +++++++
 
+error[E0107]: trait takes 1 generic argument but 2 generic arguments were supplied
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:20:46
+   |
+LL | fn func<T: Trait<u32, String>>(t: T) -> impl Trait<(), i32> {
+   |                                              ^^^^^ expected 1 generic argument
+   |
+note: trait defined here, with 1 generic parameter: `T`
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:5:11
+   |
+LL | pub trait Trait<T> {
+   |           ^^^^^ -
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: replace the generic bound with the associated type
+   |
+LL | fn func<T: Trait<u32, String>>(t: T) -> impl Trait<(), Assoc = i32> {
+   |                                                        +++++++
+
 error[E0282]: type annotations needed
   --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:20:41
    |
@@ -61,7 +78,7 @@ LL | fn func<T: Trait<u32, String>>(t: T) -> impl Trait<(), i32> {
    |                                         ^^^^^^^^^^^^^^^^^^^ cannot infer type
 
 error[E0107]: trait takes 1 generic argument but 2 generic arguments were supplied
-  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:27:18
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:28:18
    |
 LL | struct Struct<T: Trait<u32, String>> {
    |                  ^^^^^ expected 1 generic argument
@@ -77,7 +94,7 @@ LL | struct Struct<T: Trait<u32, Assoc = String>> {
    |                             +++++++
 
 error[E0107]: trait takes 1 generic argument but 2 generic arguments were supplied
-  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:32:23
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:33:23
    |
 LL | trait AnotherTrait<T: Trait<T, i32>> {}
    |                       ^^^^^ expected 1 generic argument
@@ -93,7 +110,7 @@ LL | trait AnotherTrait<T: Trait<T, Assoc = i32>> {}
    |                                +++++++
 
 error[E0107]: trait takes 1 generic argument but 2 generic arguments were supplied
-  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:35:9
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:36:9
    |
 LL | impl<T: Trait<u32, String>> Struct<T> {}
    |         ^^^^^ expected 1 generic argument
@@ -109,7 +126,7 @@ LL | impl<T: Trait<u32, Assoc = String>> Struct<T> {}
    |                    +++++++
 
 error[E0107]: struct takes 1 generic argument but 2 generic arguments were supplied
-  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:41:58
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:42:58
    |
 LL | impl<T: Trait<u32, Assoc=String>, U> YetAnotherTrait for Struct<T, U> {}
    |                                                          ^^^^^^    - help: remove this generic argument
@@ -117,12 +134,12 @@ LL | impl<T: Trait<u32, Assoc=String>, U> YetAnotherTrait for Struct<T, U> {}
    |                                                          expected 1 generic argument
    |
 note: struct defined here, with 1 generic parameter: `T`
-  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:27:8
+  --> $DIR/116464-invalid-assoc-type-suggestion-in-trait-impl.rs:28:8
    |
 LL | struct Struct<T: Trait<u32, String>> {
    |        ^^^^^^ -
 
-error: aborting due to 10 previous errors
+error: aborting due to 11 previous errors
 
 Some errors have detailed explanations: E0107, E0207, E0282.
 For more information about an error, try `rustc --explain E0107`.
diff --git a/tests/ui/traits/impl-of-supertrait-has-wrong-lifetime-parameters.stderr b/tests/ui/traits/impl-of-supertrait-has-wrong-lifetime-parameters.stderr
index 092776edea7..8bf8536c74e 100644
--- a/tests/ui/traits/impl-of-supertrait-has-wrong-lifetime-parameters.stderr
+++ b/tests/ui/traits/impl-of-supertrait-has-wrong-lifetime-parameters.stderr
@@ -4,16 +4,16 @@ error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'b` d
 LL | impl<'a,'b> T2<'a, 'b> for S<'a, 'b> {
    |                            ^^^^^^^^^
    |
-note: first, the lifetime cannot outlive the lifetime `'a` as defined here...
-  --> $DIR/impl-of-supertrait-has-wrong-lifetime-parameters.rs:24:6
-   |
-LL | impl<'a,'b> T2<'a, 'b> for S<'a, 'b> {
-   |      ^^
-note: ...but the lifetime must also be valid for the lifetime `'b` as defined here...
+note: first, the lifetime cannot outlive the lifetime `'b` as defined here...
   --> $DIR/impl-of-supertrait-has-wrong-lifetime-parameters.rs:24:9
    |
 LL | impl<'a,'b> T2<'a, 'b> for S<'a, 'b> {
    |         ^^
+note: ...but the lifetime must also be valid for the lifetime `'a` as defined here...
+  --> $DIR/impl-of-supertrait-has-wrong-lifetime-parameters.rs:24:6
+   |
+LL | impl<'a,'b> T2<'a, 'b> for S<'a, 'b> {
+   |      ^^
 note: ...so that the types are compatible
   --> $DIR/impl-of-supertrait-has-wrong-lifetime-parameters.rs:24:28
    |
diff --git a/tests/ui/traits/matching-lifetimes.stderr b/tests/ui/traits/matching-lifetimes.stderr
index f8119ed415d..8a802d57f5c 100644
--- a/tests/ui/traits/matching-lifetimes.stderr
+++ b/tests/ui/traits/matching-lifetimes.stderr
@@ -6,16 +6,16 @@ LL |     fn foo(x: Foo<'b,'a>) {
    |
    = note: expected signature `fn(Foo<'a, 'b>)`
               found signature `fn(Foo<'b, 'a>)`
-note: the lifetime `'b` as defined here...
-  --> $DIR/matching-lifetimes.rs:13:9
-   |
-LL | impl<'a,'b> Tr for Foo<'a,'b> {
-   |         ^^
-note: ...does not necessarily outlive the lifetime `'a` as defined here
+note: the lifetime `'a` as defined here...
   --> $DIR/matching-lifetimes.rs:13:6
    |
 LL | impl<'a,'b> Tr for Foo<'a,'b> {
    |      ^^
+note: ...does not necessarily outlive the lifetime `'b` as defined here
+  --> $DIR/matching-lifetimes.rs:13:9
+   |
+LL | impl<'a,'b> Tr for Foo<'a,'b> {
+   |         ^^
 
 error[E0308]: method not compatible with trait
   --> $DIR/matching-lifetimes.rs:14:5
@@ -25,16 +25,16 @@ LL |     fn foo(x: Foo<'b,'a>) {
    |
    = note: expected signature `fn(Foo<'a, 'b>)`
               found signature `fn(Foo<'b, 'a>)`
-note: the lifetime `'a` as defined here...
-  --> $DIR/matching-lifetimes.rs:13:6
-   |
-LL | impl<'a,'b> Tr for Foo<'a,'b> {
-   |      ^^
-note: ...does not necessarily outlive the lifetime `'b` as defined here
+note: the lifetime `'b` as defined here...
   --> $DIR/matching-lifetimes.rs:13:9
    |
 LL | impl<'a,'b> Tr for Foo<'a,'b> {
    |         ^^
+note: ...does not necessarily outlive the lifetime `'a` as defined here
+  --> $DIR/matching-lifetimes.rs:13:6
+   |
+LL | impl<'a,'b> Tr for Foo<'a,'b> {
+   |      ^^
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/traits/span-bug-issue-121414.rs b/tests/ui/traits/span-bug-issue-121414.rs
index 6fbe2c179c6..ec38d8c2de6 100644
--- a/tests/ui/traits/span-bug-issue-121414.rs
+++ b/tests/ui/traits/span-bug-issue-121414.rs
@@ -6,7 +6,8 @@ impl<'a> Bar for Foo<'f> { //~ ERROR undeclared lifetime
     type Type = u32;
 }
 
-fn test() //~ ERROR implementation of `Bar` is not general enough
+fn test() //~ ERROR the trait bound `for<'a> Foo<'a>: Bar` is not satisfied
+          //~| ERROR the trait bound `for<'a> Foo<'a>: Bar` is not satisfied
 where
     for<'a> <Foo<'a> as Bar>::Type: Sized,
 {
diff --git a/tests/ui/traits/span-bug-issue-121414.stderr b/tests/ui/traits/span-bug-issue-121414.stderr
index 3c97f64e781..e2ef6672cd5 100644
--- a/tests/ui/traits/span-bug-issue-121414.stderr
+++ b/tests/ui/traits/span-bug-issue-121414.stderr
@@ -6,15 +6,22 @@ LL | impl<'a> Bar for Foo<'f> {
    |      |
    |      help: consider introducing lifetime `'f` here: `'f,`
 
-error: implementation of `Bar` is not general enough
+error[E0277]: the trait bound `for<'a> Foo<'a>: Bar` is not satisfied
+  --> $DIR/span-bug-issue-121414.rs:9:1
+   |
+LL | / fn test()
+LL | |
+LL | | where
+LL | |     for<'a> <Foo<'a> as Bar>::Type: Sized,
+   | |__________________________________________^ the trait `for<'a> Bar` is not implemented for `Foo<'a>`
+
+error[E0277]: the trait bound `for<'a> Foo<'a>: Bar` is not satisfied
   --> $DIR/span-bug-issue-121414.rs:9:4
    |
 LL | fn test()
-   |    ^^^^ implementation of `Bar` is not general enough
-   |
-   = note: `Bar` would have to be implemented for the type `Foo<'0>`, for any lifetime `'0`...
-   = note: ...but `Bar` is actually implemented for the type `Foo<'1>`, for some specific lifetime `'1`
+   |    ^^^^ the trait `for<'a> Bar` is not implemented for `Foo<'a>`
 
-error: aborting due to 2 previous errors
+error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0261`.
+Some errors have detailed explanations: E0261, E0277.
+For more information about an error, try `rustc --explain E0261`.
diff --git a/tests/ui/traits/suggest-fully-qualified-closure.rs b/tests/ui/traits/suggest-fully-qualified-closure.rs
index f401a3012da..3d28a4e6bf5 100644
--- a/tests/ui/traits/suggest-fully-qualified-closure.rs
+++ b/tests/ui/traits/suggest-fully-qualified-closure.rs
@@ -1,7 +1,5 @@
 //@ check-fail
 //@ known-bug: #103705
-//@ normalize-stderr-test "\{closure@.*\}" -> "{closure@}"
-//@ normalize-stderr-test "\+* ~" -> "+++ ~"
 
 // The output of this currently suggests writing a closure in the qualified path.
 
diff --git a/tests/ui/traits/suggest-fully-qualified-closure.stderr b/tests/ui/traits/suggest-fully-qualified-closure.stderr
index e077bd7ac2a..a2c1115e673 100644
--- a/tests/ui/traits/suggest-fully-qualified-closure.stderr
+++ b/tests/ui/traits/suggest-fully-qualified-closure.stderr
@@ -1,11 +1,11 @@
 error[E0283]: type annotations needed
-  --> $DIR/suggest-fully-qualified-closure.rs:23:7
+  --> $DIR/suggest-fully-qualified-closure.rs:21:7
    |
 LL |     q.lol(||());
    |       ^^^
    |
 note: multiple `impl`s satisfying `Qqq: MyTrait<_>` found
-  --> $DIR/suggest-fully-qualified-closure.rs:14:1
+  --> $DIR/suggest-fully-qualified-closure.rs:12:1
    |
 LL | impl MyTrait<u32> for Qqq{
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -14,8 +14,8 @@ LL | impl MyTrait<u64> for Qqq{
    | ^^^^^^^^^^^^^^^^^^^^^^^^^
 help: try using a fully qualified path to specify the expected types
    |
-LL |     <Qqq as MyTrait<T>>::lol::<{closure@}>(&q, ||());
-   |     +++ ~
+LL |     <Qqq as MyTrait<T>>::lol::<_>(&q, ||());
+   |     +++++++++++++++++++++++++++++++ ~
 
 error: aborting due to 1 previous error
 
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs b/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs
new file mode 100644
index 00000000000..ef9fe604ea7
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs
@@ -0,0 +1,25 @@
+//! This test used to ICE because, while an error was emitted,
+//! we still tried to remap generic params used in the hidden type
+//! to the ones of the opaque type definition.
+
+//@ edition: 2021
+
+#![feature(type_alias_impl_trait)]
+use std::future::Future;
+
+type FutNothing<'a> = impl 'a + Future<Output = ()>;
+//~^ ERROR: unconstrained opaque type
+
+async fn operation(_: &mut ()) -> () {
+    //~^ ERROR: concrete type differs from previous
+    call(operation).await
+}
+
+async fn call<F>(_f: F)
+where
+    for<'any> F: FnMut(&'any mut ()) -> FutNothing<'any>,
+{
+    //~^ ERROR: expected generic lifetime parameter, found `'any`
+}
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr b/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr
new file mode 100644
index 00000000000..d7a0452727e
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr
@@ -0,0 +1,34 @@
+error: unconstrained opaque type
+  --> $DIR/hkl_forbidden4.rs:10:23
+   |
+LL | type FutNothing<'a> = impl 'a + Future<Output = ()>;
+   |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: `FutNothing` must be used in combination with a concrete type within the same module
+
+error: concrete type differs from previous defining opaque type use
+  --> $DIR/hkl_forbidden4.rs:13:1
+   |
+LL | async fn operation(_: &mut ()) -> () {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `FutNothing<'_>`, got `{async fn body@$DIR/hkl_forbidden4.rs:13:38: 16:2}`
+   |
+note: previous use here
+  --> $DIR/hkl_forbidden4.rs:15:5
+   |
+LL |     call(operation).await
+   |     ^^^^^^^^^^^^^^^
+
+error[E0792]: expected generic lifetime parameter, found `'any`
+  --> $DIR/hkl_forbidden4.rs:21:1
+   |
+LL |   type FutNothing<'a> = impl 'a + Future<Output = ()>;
+   |                   -- this generic parameter must be used with a generic lifetime parameter
+...
+LL | / {
+LL | |
+LL | | }
+   | |_^
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/not_well_formed.fixed b/tests/ui/type-alias-impl-trait/not_well_formed.fixed
deleted file mode 100644
index bd45d8cddae..00000000000
--- a/tests/ui/type-alias-impl-trait/not_well_formed.fixed
+++ /dev/null
@@ -1,19 +0,0 @@
-//@ run-rustfix
-#![feature(type_alias_impl_trait)]
-#![allow(dead_code)]
-
-fn main() {}
-
-trait TraitWithAssoc {
-    type Assoc;
-}
-
-type Foo<V: TraitWithAssoc> = impl Trait<V::Assoc>; //~ associated type `Assoc` not found for `V`
-
-trait Trait<U> {}
-
-impl<W> Trait<W> for () {}
-
-fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T> {
-    ()
-}
diff --git a/tests/ui/type-alias-impl-trait/not_well_formed.rs b/tests/ui/type-alias-impl-trait/not_well_formed.rs
index 7b5444ae0d3..0cf8d41c7fd 100644
--- a/tests/ui/type-alias-impl-trait/not_well_formed.rs
+++ b/tests/ui/type-alias-impl-trait/not_well_formed.rs
@@ -1,4 +1,4 @@
-//@ run-rustfix
+// Can't rustfix because we apply the suggestion twice :^(
 #![feature(type_alias_impl_trait)]
 #![allow(dead_code)]
 
@@ -8,7 +8,9 @@ trait TraitWithAssoc {
     type Assoc;
 }
 
-type Foo<V> = impl Trait<V::Assoc>; //~ associated type `Assoc` not found for `V`
+type Foo<V> = impl Trait<V::Assoc>;
+//~^ associated type `Assoc` not found for `V`
+//~| associated type `Assoc` not found for `V`
 
 trait Trait<U> {}
 
diff --git a/tests/ui/type-alias-impl-trait/not_well_formed.stderr b/tests/ui/type-alias-impl-trait/not_well_formed.stderr
index dbd80ffa4f6..a2944a1acb9 100644
--- a/tests/ui/type-alias-impl-trait/not_well_formed.stderr
+++ b/tests/ui/type-alias-impl-trait/not_well_formed.stderr
@@ -9,6 +9,18 @@ help: consider restricting type parameter `V`
 LL | type Foo<V: TraitWithAssoc> = impl Trait<V::Assoc>;
    |           ++++++++++++++++
 
-error: aborting due to 1 previous error
+error[E0220]: associated type `Assoc` not found for `V`
+  --> $DIR/not_well_formed.rs:11:29
+   |
+LL | type Foo<V> = impl Trait<V::Assoc>;
+   |                             ^^^^^ there is an associated type `Assoc` in the trait `TraitWithAssoc`
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+help: consider restricting type parameter `V`
+   |
+LL | type Foo<V: TraitWithAssoc> = impl Trait<V::Assoc>;
+   |           ++++++++++++++++
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0220`.
diff --git a/tests/ui/typeck/escaping_bound_vars.rs b/tests/ui/typeck/escaping_bound_vars.rs
index f886388bfbd..985a3fdbccf 100644
--- a/tests/ui/typeck/escaping_bound_vars.rs
+++ b/tests/ui/typeck/escaping_bound_vars.rs
@@ -11,9 +11,6 @@ where
     (): Test<{ 1 + (<() as Elide(&())>::call) }>,
     //~^ ERROR cannot capture late-bound lifetime in constant
     //~| ERROR associated type bindings are not allowed here
-    //~| ERROR the trait bound `(): Elide<(&(),)>` is not satisfied
-    //~| ERROR the trait bound `(): Elide<(&(),)>` is not satisfied
-    //~| ERROR cannot add
 {
 }
 
diff --git a/tests/ui/typeck/escaping_bound_vars.stderr b/tests/ui/typeck/escaping_bound_vars.stderr
index 8c7dcdb7f16..bd9c95fab97 100644
--- a/tests/ui/typeck/escaping_bound_vars.stderr
+++ b/tests/ui/typeck/escaping_bound_vars.stderr
@@ -12,49 +12,6 @@ error[E0229]: associated type bindings are not allowed here
 LL |     (): Test<{ 1 + (<() as Elide(&())>::call) }>,
    |                            ^^^^^^^^^^ associated type not allowed here
 
-error[E0277]: the trait bound `(): Elide<(&(),)>` is not satisfied
-  --> $DIR/escaping_bound_vars.rs:11:22
-   |
-LL |     (): Test<{ 1 + (<() as Elide(&())>::call) }>,
-   |                      ^^ the trait `Elide<(&(),)>` is not implemented for `()`
-   |
-help: this trait has no implementations, consider adding one
-  --> $DIR/escaping_bound_vars.rs:5:1
-   |
-LL | trait Elide<T> {
-   | ^^^^^^^^^^^^^^
-
-error[E0277]: cannot add `fn() {<() as Elide<(&(),)>>::call}` to `{integer}`
-  --> $DIR/escaping_bound_vars.rs:11:18
-   |
-LL |     (): Test<{ 1 + (<() as Elide(&())>::call) }>,
-   |                  ^ no implementation for `{integer} + fn() {<() as Elide<(&(),)>>::call}`
-   |
-   = help: the trait `Add<fn() {<() as Elide<(&(),)>>::call}>` is not implemented for `{integer}`
-   = help: the following other types implement trait `Add<Rhs>`:
-             <isize as Add>
-             <isize as Add<&isize>>
-             <i8 as Add>
-             <i8 as Add<&i8>>
-             <i16 as Add>
-             <i16 as Add<&i16>>
-             <i32 as Add>
-             <i32 as Add<&i32>>
-           and 48 others
-
-error[E0277]: the trait bound `(): Elide<(&(),)>` is not satisfied
-  --> $DIR/escaping_bound_vars.rs:11:18
-   |
-LL |     (): Test<{ 1 + (<() as Elide(&())>::call) }>,
-   |                  ^ the trait `Elide<(&(),)>` is not implemented for `()`
-   |
-help: this trait has no implementations, consider adding one
-  --> $DIR/escaping_bound_vars.rs:5:1
-   |
-LL | trait Elide<T> {
-   | ^^^^^^^^^^^^^^
-
-error: aborting due to 5 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0229, E0277.
-For more information about an error, try `rustc --explain E0229`.
+For more information about this error, try `rustc --explain E0229`.
diff --git a/tests/ui/typeck/issue-91267.stderr b/tests/ui/typeck/issue-91267.stderr
index 7e48b251980..399309d0ec4 100644
--- a/tests/ui/typeck/issue-91267.stderr
+++ b/tests/ui/typeck/issue-91267.stderr
@@ -17,6 +17,8 @@ LL | fn main() {
    |          - expected `()` because of default return type
 LL |     type_ascribe!(0, u8<e<5>=e>)
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `u8`
+   |
+   = note: this error originates in the macro `type_ascribe` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/unboxed-closures/unboxed-closure-sugar-region.rs b/tests/ui/unboxed-closures/unboxed-closure-sugar-region.rs
index 8537eb71774..ea73b8b3c4a 100644
--- a/tests/ui/unboxed-closures/unboxed-closure-sugar-region.rs
+++ b/tests/ui/unboxed-closures/unboxed-closure-sugar-region.rs
@@ -33,7 +33,6 @@ fn test2(x: &dyn Foo<(isize,),Output=()>, y: &dyn Foo(isize)) {
     //~^ ERROR trait takes 1 lifetime argument but 0 lifetime arguments were supplied
     // Here, the omitted lifetimes are expanded to distinct things.
     same_type(x, y)
-    //~^ ERROR borrowed data escapes outside of function
 }
 
 fn main() { }
diff --git a/tests/ui/unboxed-closures/unboxed-closure-sugar-region.stderr b/tests/ui/unboxed-closures/unboxed-closure-sugar-region.stderr
index 6e6c649ca3d..d73aef851fd 100644
--- a/tests/ui/unboxed-closures/unboxed-closure-sugar-region.stderr
+++ b/tests/ui/unboxed-closures/unboxed-closure-sugar-region.stderr
@@ -34,22 +34,6 @@ note: trait defined here, with 1 lifetime parameter: `'a`
 LL | trait Foo<'a,T> {
    |       ^^^ --
 
-error[E0521]: borrowed data escapes outside of function
-  --> $DIR/unboxed-closure-sugar-region.rs:35:5
-   |
-LL | fn test2(x: &dyn Foo<(isize,),Output=()>, y: &dyn Foo(isize)) {
-   |          -                                - `y` declared here, outside of the function body
-   |          |
-   |          `x` is a reference that is only valid in the function body
-   |          has type `&dyn Foo<'1, (isize,), Output = ()>`
-...
-LL |     same_type(x, y)
-   |     ^^^^^^^^^^^^^^^
-   |     |
-   |     `x` escapes the function body here
-   |     argument requires that `'1` must outlive `'static`
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors
 
-Some errors have detailed explanations: E0107, E0521.
-For more information about an error, try `rustc --explain E0107`.
+For more information about this error, try `rustc --explain E0107`.
diff --git a/tests/ui/unboxed-closures/unboxed-closures-type-mismatch-closure-from-another-scope.stderr b/tests/ui/unboxed-closures/unboxed-closures-type-mismatch-closure-from-another-scope.stderr
index 1470c32d7de..5f22c781345 100644
--- a/tests/ui/unboxed-closures/unboxed-closures-type-mismatch-closure-from-another-scope.stderr
+++ b/tests/ui/unboxed-closures/unboxed-closures-type-mismatch-closure-from-another-scope.stderr
@@ -26,11 +26,11 @@ note: closure parameter defined here
 LL |         let mut closure = expect_sig(|p, y| *p = y);
    |                                       ^
 
-error[E0425]: cannot find function `deref` in this scope
+error[E0423]: expected function, found macro `deref`
   --> $DIR/unboxed-closures-type-mismatch-closure-from-another-scope.rs:13:5
    |
 LL |     deref(p);
-   |     ^^^^^ not found in this scope
+   |     ^^^^^ not a function
    |
 help: use the `.` operator to call the method `Deref::deref` on `&&()`
    |
@@ -40,5 +40,5 @@ LL +     p.deref();
 
 error: aborting due to 4 previous errors
 
-Some errors have detailed explanations: E0308, E0425.
+Some errors have detailed explanations: E0308, E0423, E0425.
 For more information about an error, try `rustc --explain E0308`.
diff --git a/tests/ui/underscore-lifetime/underscore-lifetime-binders.rs b/tests/ui/underscore-lifetime/underscore-lifetime-binders.rs
index ebc38798544..3d049cc5639 100644
--- a/tests/ui/underscore-lifetime/underscore-lifetime-binders.rs
+++ b/tests/ui/underscore-lifetime/underscore-lifetime-binders.rs
@@ -14,7 +14,6 @@ fn meh() -> Box<dyn for<'_> Meh<'_>> //~ ERROR cannot be used here
 }
 
 fn foo2(_: &'_ u8, y: &'_ u8) -> &'_ u8 { y } //~ ERROR missing lifetime specifier
-//~^ ERROR lifetime may not live long enough
 
 fn main() {
     let x = 5;
diff --git a/tests/ui/underscore-lifetime/underscore-lifetime-binders.stderr b/tests/ui/underscore-lifetime/underscore-lifetime-binders.stderr
index 5d2954d1d71..cd74d27dcb5 100644
--- a/tests/ui/underscore-lifetime/underscore-lifetime-binders.stderr
+++ b/tests/ui/underscore-lifetime/underscore-lifetime-binders.stderr
@@ -45,15 +45,7 @@ help: consider introducing a named lifetime parameter
 LL | fn foo2<'a>(_: &'a u8, y: &'a u8) -> &'a u8 { y }
    |        ++++     ~~         ~~         ~~
 
-error: lifetime may not live long enough
-  --> $DIR/underscore-lifetime-binders.rs:16:43
-   |
-LL | fn foo2(_: &'_ u8, y: &'_ u8) -> &'_ u8 { y }
-   |                       -                   ^ returning this value requires that `'1` must outlive `'static`
-   |                       |
-   |                       let's call the lifetime of this reference `'1`
-
-error: aborting due to 6 previous errors
+error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0106, E0637.
 For more information about an error, try `rustc --explain E0106`.
diff --git a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs
new file mode 100644
index 00000000000..107cfbb9ff6
--- /dev/null
+++ b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.rs
@@ -0,0 +1,12 @@
+trait Trait<const N: Trait = bar> {
+//~^ ERROR cannot find value `bar` in this scope
+//~| ERROR cycle detected when computing type of `Trait::N`
+//~| ERROR cycle detected when computing type of `Trait::N`
+//~| ERROR `(dyn Trait<{const error}> + 'static)` is forbidden as the type of a const generic parameter
+//~| WARN trait objects without an explicit `dyn` are deprecated
+//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+    fn fnc(&self) {
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr
new file mode 100644
index 00000000000..2d5a0ede962
--- /dev/null
+++ b/tests/ui/wf/ice-hir-wf-check-anon-const-issue-122199.stderr
@@ -0,0 +1,60 @@
+error[E0425]: cannot find value `bar` in this scope
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:30
+   |
+LL | trait Trait<const N: Trait = bar> {
+   |                              ^^^ not found in this scope
+
+warning: trait objects without an explicit `dyn` are deprecated
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:22
+   |
+LL | trait Trait<const N: Trait = bar> {
+   |                      ^^^^^
+   |
+   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
+   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
+   = note: `#[warn(bare_trait_objects)]` on by default
+help: if this is an object-safe trait, use `dyn`
+   |
+LL | trait Trait<const N: dyn Trait = bar> {
+   |                      +++
+
+error[E0391]: cycle detected when computing type of `Trait::N`
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:22
+   |
+LL | trait Trait<const N: Trait = bar> {
+   |                      ^^^^^
+   |
+   = note: ...which immediately requires computing type of `Trait::N` again
+note: cycle used when computing explicit predicates of trait `Trait`
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:1
+   |
+LL | trait Trait<const N: Trait = bar> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
+
+error[E0391]: cycle detected when computing type of `Trait::N`
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:13
+   |
+LL | trait Trait<const N: Trait = bar> {
+   |             ^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: ...which immediately requires computing type of `Trait::N` again
+note: cycle used when computing explicit predicates of trait `Trait`
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:1
+   |
+LL | trait Trait<const N: Trait = bar> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
+
+error: `(dyn Trait<{const error}> + 'static)` is forbidden as the type of a const generic parameter
+  --> $DIR/ice-hir-wf-check-anon-const-issue-122199.rs:1:22
+   |
+LL | trait Trait<const N: Trait = bar> {
+   |                      ^^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+
+error: aborting due to 4 previous errors; 1 warning emitted
+
+Some errors have detailed explanations: E0391, E0425.
+For more information about an error, try `rustc --explain E0391`.
diff --git a/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.rs b/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.rs
index 0be5127dcc4..e6d4e2ee01a 100644
--- a/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.rs
+++ b/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.rs
@@ -14,4 +14,5 @@ impl Trait for Ref {} //~ ERROR:  implicit elided lifetime not allowed here
 
 extern "C" {
     pub fn repro(_: Wrapper<Ref>);
+    //~^ ERROR the trait bound `Ref<'_>: Trait` is not satisfied
 }
diff --git a/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.stderr b/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.stderr
index 0af4ab022e1..59b55b2732d 100644
--- a/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.stderr
+++ b/tests/ui/wf/wf-in-foreign-fn-decls-issue-80468.stderr
@@ -9,6 +9,19 @@ help: indicate the anonymous lifetime
 LL | impl Trait for Ref<'_> {}
    |                   ++++
 
-error: aborting due to 1 previous error
+error[E0277]: the trait bound `Ref<'_>: Trait` is not satisfied
+  --> $DIR/wf-in-foreign-fn-decls-issue-80468.rs:16:21
+   |
+LL |     pub fn repro(_: Wrapper<Ref>);
+   |                     ^^^^^^^^^^^^ the trait `Trait` is not implemented for `Ref<'_>`
+   |
+note: required by a bound in `Wrapper`
+  --> $DIR/wf-in-foreign-fn-decls-issue-80468.rs:8:23
+   |
+LL | pub struct Wrapper<T: Trait>(T);
+   |                       ^^^^^ required by this bound in `Wrapper`
+
+error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0726`.
+Some errors have detailed explanations: E0277, E0726.
+For more information about an error, try `rustc --explain E0277`.